Back Pain: Why Not to Get a Scan, What Actually Helps in the First Six Weeks and the Signs That Need Hours
Two things are true about back pain at the same time, and holding both is the whole skill.
The first is that it is almost never dangerous. The overwhelming majority of episodes have no specific cause that can be found, and they settle. The second is that a small number of presentations need attention within hours, and they are recognisable.
So the useful page is not reassurance and not alarm. It is: here is what needs checking today, here is what the first six weeks should look like, and here are the two most common ways people make this worse for themselves.
🚨 Go to emergency care now if any of these are present:
🔹 Numbness in the saddle area — the inner thighs, buttocks, genitals or around the anus. Including numbness noticed only when wiping
🔹 Difficulty passing urine, or losing control of bladder or bowel, or no longer feeling the urge
🔹 Weakness or numbness spreading into both legs
🔹 New sexual numbness
This combination can mean compression of the nerve bundle at the base of the spine. It is a surgical emergency measured in hours, not days, and delay causes permanent loss of bladder, bowel and sexual function. Do not wait for a routine appointment and do not wait until morning.
🚩 The other things that need a doctor rather than a plan
Beyond the above, a handful of features suggest the pain is coming from something specific. Each is uncommon; together they are the reason anyone asks about them at all.
- 🌡️ Fever, chills, or feeling systemically unwell with back pain — more concerning with a weakened immune system, recent infection, injected drug use or recent spinal procedure
- 🦴 Pain after a fall or impact, and in anyone over about 65, on long-term steroids, or with known osteoporosis — a vertebral fracture can follow a minor stumble or even a sneeze
- 🏥 A history of cancer, with new persistent back pain
- ⚖️ Unexplained weight loss, or pain that is worse lying down and wakes you in the night, and does not ease with position change
- 📈 First episode of significant back pain over 50, or under 20
- 📉 Progressive weakness in one leg, such as a foot that catches or slaps when walking
- 🩸 Over 60 with a tearing or ripping pain, or a pulsating sensation in the abdomen — this is a vascular emergency rather than a back problem
Pain that is worse at rest and better with movement points in a different direction again, and that one has its own section further down because it is missed for years.
📋 Three categories, and why the split matters
| Category | Share of cases | What it looks like |
|---|---|---|
| Non-specific low back pain | The large majority | Ache or stiffness across the lower back, sometimes into the buttock, worse with certain movements, no single identifiable structure to blame. No scan will explain it |
| Radicular pain — sciatica | Perhaps one in ten | Pain travelling down the leg below the knee in a line, often with tingling or numbness in a defined patch. Usually worse than the back pain itself |
| Specific or serious causes | Under one in twenty | Infection, fracture, cancer, inflammatory disease, cauda equina — the red flags above |
The point of the split is that the first category does not need investigating and the third does, and confusing them produces both unnecessary scans and missed diagnoses.
📷 Why a scan usually makes things worse
This is the strongest recommendation in every back pain guideline and the hardest to accept, so here is the actual reasoning.
📌 The findings on a scan are present in people with no pain at all. Disc degeneration appears on imaging in roughly a third of symptom-free people in their twenties and in nearly all symptom-free people in their eighties. Disc bulges, annular tears and facet changes are similarly common in people who feel nothing.
So a scan of a painful back will show something. It will show the same things it would have shown last year, and the same things it shows in the person sitting next to you who feels fine.
What follows from that is measurable rather than theoretical. People who get imaged early for ordinary back pain do not recover faster. They report more pain and worse function at follow-up, they undergo more injections and more surgery, and they are more likely to believe their spine is damaged — which itself predicts a worse outcome, because it reduces movement and increases guarding.
Reading degenerative disc disease on a report is a particularly unfortunate piece of language. It describes the normal appearance of a spine that has been used, in the same way that grey hair describes a normal head. It is not a disease and it is not progressive damage.
When imaging is appropriate: any red flag above, sciatica that is severe or persisting beyond six to eight weeks with surgery genuinely being considered, or progressive neurological loss. Otherwise the answer to should I get an MRI is almost always no, and that is good news rather than a refusal.
⏳ What normally happens, with timings
Knowing the shape of recovery prevents the two classic errors: panicking in week one, and giving up in week three.
- 📅 Days 1 to 3 are usually the worst. Movement is guarded, getting out of a chair is the hardest moment, and the pain can be severe enough to feel alarming without being dangerous
- 📈 Most of the improvement happens in the first two to six weeks, and often sooner
- 🦿 Sciatica takes longer — weeks to a few months — and around nine in ten cases settle without surgery. A disc protrusion shrinks on its own; this is well documented on repeat scans
- 🔄 Recurrence is common, with roughly half of people having another episode within a year. That is the normal course of a sensitive back, not evidence that something was missed
- 📉 Lingering mild stiffness after the episode settles is usual and fades
One caution about progress: measure it by function rather than pain score. Sitting tolerance, walking distance, sleeping through, and how quickly a bad day recovers are all more sensitive to real improvement than a number out of ten.
🛏️ The first week: what to do and what not to
The single strongest piece of advice in this whole subject is also the least intuitive.
⚠️ Do not go to bed. Bed rest for back pain is not neutral, it is actively harmful — it prolongs the episode, increases stiffness, weakens the muscles that support the spine, and raises the risk of the pain becoming persistent. The old advice to lie flat for a week has been reversed for decades and still circulates.
Lying down for an hour when the pain spikes is fine. Spending days there is not.
What to do instead:
- 🚶 Walk, little and often. Three to five minutes every couple of hours beats one long walk. Walking is the single most useful activity in the acute phase
- 🪑 Break up sitting. Roughly ten minutes seated, then two minutes standing or walking. Prolonged sitting is the position most people find worst
- 🌡️ Heat for stiffness and muscle guarding — 15 to 20 minutes, a warm shower works. Cold suits some people better in the first day or two; both are reasonable and neither changes the outcome, so use whichever helps you move
- 🛌 Sleep however hurts least. On your side with knees bent and a pillow between them, or on your back with a pillow under the knees. There is no correct posture, and a firm mattress is not better — medium firmness performs best in trials
- 🏃 Keep doing what you can of normal life. Staying at work, modified if necessary, produces better outcomes than signing off
- 🚫 Do not repeatedly test the painful movement to see if it still hurts. It will, and each test renews the guarding
- 🚫 Do not stretch hard into pain, and leave heavy lifting and loaded bending until the acute phase passes
💊 Medication: what to take and for how long
Medication here has one job: to let you move normally while the episode resolves. It is a bridge, not a treatment.
| Option | Dosing | Where it fits |
|---|---|---|
| Diclofenac | 50 mg up to three times daily, maximum 150 mg a day, with food | First line. Strongly effective. Short courses rather than ongoing use |
| Naproxen | 250 to 500 mg twice daily | Twice-daily convenience, and among the more favourable cardiovascular profiles in the class |
| Ibuprofen | 400 mg three times daily | Widely available, needs frequent dosing |
| Meloxicam | 7.5 to 15 mg once daily | Once daily, somewhat gentler on the stomach |
| Celecoxib | 100 to 200 mg | Where stomach risk is the main concern |
| Methocarbamol | 1500 mg four times daily for 2 to 3 days, then 750 mg four times daily | Added for genuine muscle spasm, short course only. See below |
| Paracetamol | Up to 4 g daily | Honest note: trials found it no better than placebo for acute low back pain. Safe, and much weaker than people assume |
The rules that matter more than the choice:
- ⏰ Short courses. Days to a couple of weeks. Anti-inflammatories are not for continuous use in back pain
- 🚫 Never two anti-inflammatories together, including a tablet plus a gel. It roughly doubles the stomach and kidney risk for almost no extra relief
- 🍽️ Always with food, and with a stomach-protecting tablet if you are over 65, have had an ulcer, or take a steroid or blood thinner
- 🛑 Stop and seek advice for black or tarry stools, vomiting blood, severe stomach pain, swollen ankles with breathlessness, or a marked drop in urine output
🚫 Two things that are offered and should not be.
Opioids. Trials show no better pain relief than anti-inflammatories for acute back pain, worse functional outcomes, and a real risk of dependence from a short course. They are not a first-line option for this and should not be the first thing tried.
Injections and surgery for non-specific back pain. Where there is no nerve compression and no specific cause, neither has good evidence. Surgery has a clear role in persistent severe sciatica with a demonstrated compression, and in the serious causes above — not in an aching lower back with a degenerate-looking scan.
📏 Why a rub-on gel will not fix your lower back
Worth its own section because it is widely recommended and it is the wrong tool for this particular job.
Anti-inflammatory gels penetrate a few centimetres. That is enough to reach a knuckle, a knee or an ankle, where the joint sits directly beneath thin skin. The joints of the lumbar spine sit under several centimetres of muscle, and nothing applied to the skin reaches them. Treatment guidelines do not recommend topical anti-inflammatories for low back pain, for exactly this reason.
What a gel may do is ease superficial muscle soreness in the overlying tissue, which is a different and smaller problem. If that is what you want it for, fine. If you are expecting it to treat the spine, it cannot, and the disappointment is predictable rather than a bad batch.
Where topical anti-inflammatories genuinely are a first-choice option — hands, knees, ankles, elbows — is covered in our guide to joint pain and which treatment reaches which joint.
💪 Muscle relaxants, and the limit on them
Robaxin (Methocarbamol) is useful for the specific situation where the back has locked into genuine spasm — the muscles are palpably hard, movement is blocked, and the anti-inflammatory alone is not breaking the cycle.
Typical use is 1500 mg four times daily for the first two to three days, then stepping down to 750 mg four times daily or 1500 mg three times. It is sedating, so the first doses are best taken when you do not need to drive, and it should not be combined with alcohol.
Two things in its favour: it is not a controlled substance, and it does not carry the dependence profile of some older muscle relaxants. And one firm limit: two to three weeks at most. Muscle relaxants help the acute lock; they do nothing for the underlying sensitivity and they are not a long-term plan.
Where spasm rather than back pain is the main story, our guides to acute muscle pain and painful muscle spasms go into the cycle in more detail.
🦿 When the pain goes down the leg
Sciatica behaves differently from back pain and deserves its own handling.
What it is: a nerve root irritated or compressed where it leaves the spine, usually by a disc protrusion. The signature is pain travelling in a line below the knee, often sharp or electric, frequently worse than the back itself, sometimes with tingling or numbness in a specific patch and occasionally with weakness.
What to expect: around nine in ten cases resolve without surgery, over weeks to a few months. Disc protrusions shrink spontaneously. The pain is often severe at first and the trajectory is still usually good.
What helps: staying active within tolerance rather than resting; walking; anti-inflammatories; and finding the positions that reduce leg symptoms rather than forcing through them. Nerve pain responds poorly to ordinary painkillers, and where it persists, agents acting on nerve signalling are sometimes added — the mechanism is covered in our guide to nerve pain and how it is treated.
When it needs escalating: progressive weakness, a foot that drops, severe pain not responding after six to eight weeks, or any of the emergency features at the top of this page.
A related pattern worth separating: leg pain and heaviness that comes on while walking and eases when you sit or lean forward over a trolley, in someone over 60, suggests narrowing of the spinal canal rather than a disc. The giveaway is the relief from bending forward — circulation-related leg pain, by contrast, eases from simply standing still.
🌅 The pattern that gets missed for years
Most back pain is worse with activity and better with rest. One important type does the opposite, and because it does not fit the expected picture it goes undiagnosed for an average of several years.
Inflammatory back pain — the family that includes axial spondyloarthritis and ankylosing spondylitis — has a recognisable combination:
- 🕥 Started before the age of 45, gradually rather than after an injury
- 📅 Present more than three months
- 🌅 Morning stiffness lasting over 30 minutes, sometimes hours
- 🏃 Better with exercise, worse with rest — the reverse of mechanical pain
- 🌛 Wakes you in the second half of the night, often needing to get up and move around
- 💊 Responds strikingly well to anti-inflammatories
- 👁️ Sometimes with: alternating buttock pain, heel or chest wall pain, a painful red eye, psoriasis, or inflammatory bowel symptoms
Several of those together, particularly in a younger adult, is worth raising explicitly, because it is a different disease with different treatment and early recognition changes the long-term outcome.
🏋️ What actually prevents the next episode
Once the acute phase settles, exercise is the only intervention with consistent evidence for reducing recurrence. Not a particular exercise — exercise.
- 🏃 Regular activity you will actually continue. Walking, swimming, cycling, gym, anything. Adherence beats the choice of programme by a wide margin
- 🍎 Hip and buttock strength, which takes load off the lower back during lifting and standing
- 🧱 Trunk endurance rather than maximum effort — holds and controlled work, not crunches
- 📈 Progress time before intensity. More consistent days, then slightly longer, then slightly harder
- 🪑 Vary your position through the day. This matters more than achieving an ideal posture, and the evidence that sitting posture itself causes back pain is weaker than the ergonomics industry suggests. The best position is the next one
- 📦 Lift with the load close to you, hinging at the hips. Backs do not break from bending; they protest from sudden unaccustomed load
- 🚬 Stop smoking — it is independently associated with back pain and with poorer disc health. See our guide to smoking cessation
- ⚖️ Weight and sleep both matter, and poor sleep amplifies pain perception measurably
Two things worth knowing about persistent back pain specifically: after about three months the pain is driven less by tissue irritation and more by a sensitised nervous system, which is why the most effective programmes at that stage combine graded exercise with psychological approaches. That is not a suggestion the pain is imaginary — it is a statement about which mechanism is now in charge, and which treatment therefore works.
❌ What does not work
- 🛏️ Bed rest. Harmful, as above
- 💊 Opioids as a first step. No better than anti-inflammatories, worse function, real dependence risk
- 🛋️ Expensive firm mattresses. Medium firmness performs best; beyond that, comfort is the only criterion
- 🦿 Back belts and supports for prevention. No evidence they prevent episodes, and prolonged use weakens the supporting muscles
- 🪝 Traction for ordinary back pain or sciatica
- ⚡ TENS machines — weak and inconsistent evidence, though harmless if you find them helpful
- 📷 Scanning without red flags, which is the most expensive item on this list in every sense
Manual therapy and massage are a partial exception: they produce modest short-term relief and can make movement easier, which is useful. They do not change the course of the condition, so they belong alongside the exercise rather than instead of it.
📞 When to seek help
🚨 Emergency, within hours: saddle numbness, difficulty passing urine or loss of bladder or bowel control, weakness or numbness in both legs, or new sexual numbness. Also: tearing abdominal or back pain over 60, or back pain with fever and feeling very unwell.
Same week:
- Progressive weakness in one leg, or a foot that drops or catches
- Back pain after a fall, or any back pain with osteoporosis, long-term steroids, or age over 65
- A history of cancer with new back pain
- Unexplained weight loss, or night pain that does not ease with position
- First significant episode over 50, or under 20
- Sciatica with numbness or weakness, rather than pain alone
Worth an appointment:
- No meaningful improvement after four to six weeks
- Morning stiffness over 30 minutes with pain better from movement, especially starting before 45 — ask about inflammatory back pain by name
- Leg pain on walking relieved by leaning forward, over 60
- Needing an anti-inflammatory most days beyond a couple of weeks
- Pain disrupting sleep most nights
- Repeated episodes — worth a referral for a structured exercise programme rather than treating each flare separately
- Low mood, or fear of movement becoming the main limitation, both of which are treatable and both of which predict persistence
- Stomach ulcer history, kidney disease, heart failure, or blood thinners — before taking anti-inflammatories at all
❓ Frequently asked questions
Do I need an MRI for back pain?
Almost never without red flags. Disc degeneration and bulges appear on scans of people with no pain at all, and people imaged early report more pain and worse function later, with more injections and surgery and no benefit.
When is back pain an emergency?
Saddle numbness, difficulty passing urine or loss of bladder or bowel control, weakness or numbness in both legs, or new sexual numbness. That combination needs emergency care within hours, not a routine appointment.
How long does lower back pain last?
Days one to three are usually worst, with most improvement in the first two to six weeks. Sciatica takes weeks to a few months and settles without surgery in around nine cases out of ten. Recurrence is common.
Should I rest in bed with back pain?
No. Bed rest prolongs the episode, increases stiffness and raises the risk of persistent pain. Short walks every couple of hours and breaking up sitting are the most useful things in the acute phase.
Does diclofenac gel work for back pain?
Not for the spine itself. Gels penetrate a few centimetres and the lumbar joints sit under several centimetres of muscle, which is why guidelines do not recommend topical anti-inflammatories for low back pain. Tablets are the route that works.
What is the diclofenac dose for back pain?
Usually 50 mg up to three times daily with food, maximum 150 mg a day, as a short course of days to a couple of weeks. Never combine two anti-inflammatories, including a tablet with a gel.
Does paracetamol help acute back pain?
Trials found it no better than placebo for acute low back pain. It is safe and much weaker than most people assume, so an anti-inflammatory is the more effective choice where it can be taken.
How long can I take a muscle relaxant?
Two to three weeks at most, and only for genuine spasm. Methocarbamol is typically 1500 mg four times daily for two to three days then stepped down. It is sedating and should not be combined with alcohol.
What does degenerative disc disease on my report mean?
It describes the normal appearance of a spine that has been used, in the way grey hair describes a normal head. It is not a disease and not progressive damage, and the same findings appear in people with no pain.
My back is stiff for an hour every morning and better when I move. Is that different?
Possibly. Morning stiffness over 30 minutes, pain better with exercise and worse with rest, waking in the second half of the night, and onset before 45 suggest inflammatory back pain, which is a different disease needing different treatment.
📑 Sources and editorial
- Clinical practice guidelines on the assessment and management of low back pain and sciatica, including recommendations against routine imaging, against bed rest and against opioids as first-line therapy
- Systematic reviews of early imaging for low back pain and its association with subsequent pain, function, procedure rates and surgery
- Prevalence studies of degenerative spinal findings on magnetic resonance imaging in asymptomatic adults by decade of age
- Natural history studies of acute low back pain and of lumbar disc herniation, including rates of spontaneous resorption and of recovery without surgery in sciatica
- Recurrence data for low back pain within twelve months of an index episode
- Randomised trials of advice to stay active compared with bed rest for acute low back pain
- Randomised trial evidence on paracetamol for acute low back pain, and comparative trials of opioids against non-steroidal anti-inflammatory drugs
- Guidance on the gastrointestinal, renal and cardiovascular risks of oral non-steroidal anti-inflammatory drugs and indications for gastroprotection
- Cochrane reviews of topical anti-inflammatory preparations by anatomical site, and guideline statements on their place in low back pain
- Prescribing information for diclofenac and for methocarbamol, including dosing schedules, duration limits and sedation
- Diagnostic criteria and guidance for cauda equina syndrome, including presenting features and time-critical management
- Red flag frameworks for vertebral fracture, spinal infection, malignancy and abdominal aortic aneurysm presenting as back pain
- Classification criteria and referral guidance for inflammatory back pain and axial spondyloarthritis, including reported diagnostic delay
- Reviews of neurogenic claudication in lumbar spinal stenosis and its differentiation from vascular claudication
- Trials of exercise therapy for prevention of recurrent low back pain, of mattress firmness, of lumbar supports, of traction and of transcutaneous electrical nerve stimulation
- Evidence on combined exercise and psychological approaches in persistent low back pain, and on central sensitisation as the dominant mechanism beyond three months
- Related reading: joint pain and which treatment reaches which joint, acute muscle pain, painful muscle spasms, osteochondrosis, nerve pain
- Related products: Voltaren (Diclofenac), Robaxin (Methocarbamol), Naprosyn (Naproxen), Mobic (Meloxicam), pain medicine category, muscle relaxers category
- RXshop Editorial Team — reviewed by Emily Chen, MD, MPH — Internal Medicine Specialist
Medical Disclaimer: The information in this article is for educational and informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek guidance from a qualified healthcare provider with any questions you may have regarding a medical condition, and before starting, stopping or changing any medication.