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Back pain is one of those things almost everyone brushes off until it stops being temporary. Around four in five adults deal with it at some point, and for roughly one in five the ache never quite fades within the usual four to six weeks. It settles in. It becomes the thing you plan your day around: which chair you sit in, how you get out of the car, whether you pick up your kid or ask someone else to. Once pain passes the three-month mark it’s officially chronic, and the question shifts from “what did I do?” to “what is actually driving this?”
That question matters, because the seven causes below respond to very different treatments. Stretching a narrowed spinal canal can make things worse. Resting a herniated disc for six weeks slows recovery. Here’s how to tell them apart.
1. Degenerative Disc Disease and Herniated Discs
Between every vertebra sits a disc, a tough cartilage cushion with a jelly-like centre. From about age 30, discs gradually lose water content and height. That process is called degenerative disc disease, and it’s less a disease than a normal feature of ageing.
The surprise is how poorly scans predict pain. Imaging research has found that close to 90% of people over 60 show some disc degeneration on an MRI, and a large share of them have no symptoms at all. A “bad disc” on a radiology report is not automatically the source of your pain.
A herniated disc is more specific. The jelly centre pushes through the outer ring and can press on a nerve root, producing pain that travels instead of staying put. The giveaway is distribution: pain shooting through the buttock into the thigh or calf, often with tingling in a precise patch of the foot, and often worse when you cough or sit for a long stretch.
2. Muscle Weakness and Deconditioning
A great deal of chronic back pain isn’t structural at all. It’s muscular, and it builds from thousands of small decisions: eight hours in a chair with no lumbar support, a laptop at chest height, a commute, an evening on the sofa, repeated for a decade.
Why “just rest it” backfires
The deep muscles that stabilise the spine, particularly the multifidus and the glutes, weaken fast when they aren’t used. Six weeks of bed rest costs a noticeable amount of strength, and weaker support muscles mean the spine tolerates less load. That’s why current guidelines favour early, gentle movement over prolonged rest.
A useful self-test: does your pain ease after a 20-minute walk and stiffen after 40 minutes of sitting? That pattern leans mechanical, and it usually responds well to a graded strengthening programme rather than passive treatment.
3. Osteoarthritis and Spinal Stenosis
Facet joints sit at the back of each vertebra and, like knees and hips, they wear with age. Bone spurs can form, and the canal carrying the spinal cord and nerve roots can narrow. That narrowing is spinal stenosis.
Stenosis has an unusual signature. Heaviness and pain in the legs come on when you stand or walk and ease when you sit down or lean forward, which is why some people get relief pushing a shopping trolley or leaning over bike handlebars. Leaning forward opens the canal fractionally. If your comfortable walking distance has been shrinking year on year, that’s the pattern to describe to a clinician.
4. Nerve Compression and Sciatica
Sciatica is a symptom, not a diagnosis. Something is irritating the sciatic nerve or one of its roots, most often at the L4-L5 or L5-S1 level. True sciatica usually reaches below the knee, follows a line down the back of the leg, and may bring numbness, pins and needles, or a weak ankle.
Nerves can also be damaged from the inside. Chronically high blood sugar is a leading cause of peripheral neuropathy, and the burning or numbness it produces gets mistaken for a mechanical back problem surprisingly often. If there’s a family history or other reason to check, it’s worth reviewing the main risk factors for diabetes before assuming your spine is at fault.
5. Inflammatory Back Pain From an Autoimmune Condition
Ankylosing spondylitis and related axial spondyloarthritis are the classic inflammatory causes, and they’re missed for years on average because the pain doesn’t follow the usual rules.
Four clues of inflammatory pain
- It starts before age 45, often in the late teens or twenties
- Morning stiffness lasts longer than 30 minutes
- Pain is worse at rest and at night, and eases with movement
- It improves within 48 hours of an NSAID such as ibuprofen
These conditions belong to the same broad family as other immune-driven illness, so it helps to recognise the early signs of autoimmune disease most people miss, especially if you also have psoriasis, recurring gut inflammation, or a persistently raised CRP.
6. Hormones, Bone Density and the Thyroid
Oestrogen does far more than regulate the menstrual cycle. It acts as a brake on bone breakdown, and when levels fall steeply through perimenopause, bone loss accelerates. Vertebral fractures from osteoporosis are a common and under-diagnosed cause of mid-back pain in women over 50, sometimes with no injury at all.
Other endocrine problems pull the same strings. An underactive thyroid can cause muscle aches, stiffness and fatigue that make movement feel harder than it should, and those symptoms get filed under “getting older” for years. A look at the thyroid symptoms most people explain away is worth five minutes. Hormonal disruption rarely arrives alone either, and the triggers overlap considerably, from sleep debt and stress to medication itself. There’s a clear breakdown of the common causes of hormonal imbalance if you want to trace the pattern.
7. Sleep, Stress and a Sensitised Nervous System
Pain isn’t a straight signal from tissue to brain. The nervous system adjusts the volume, and it sets that volume partly on how rested and safe you feel. Keep the volume turned up long enough and ordinary sensations start registering as painful, a process called central sensitisation.
The sleep link is measurable. In experimental studies, healthy volunteers deprived of deep sleep report more pain from the same stimulus and recover more slowly. Chronic pain then fragments sleep, and the cycle tightens. Low iron and other forms of anaemia can add a layer of exhaustion that makes activity feel impossible, and the picture differs depending on which type of anaemia you’re dealing with.
Signs the Pain Needs a Doctor, Not a Stretch
Most chronic back pain is manageable. Some isn’t, and knowing the red flags matters more than naming the cause.
- Numbness around the groin or inner thighs, new bladder or bowel problems, or weakness in both legs. This can signal cauda equina syndrome, which is a surgical emergency.
- Pain that wakes you at night and doesn’t change when you shift position
- Unexplained weight loss, fever, or a personal history of cancer
- Progressive weakness, or a foot that drags when you walk
- Pain that began after a fall or other significant trauma
If any of those apply, book an appointment this week rather than waiting out the six-week rule.
Matching the Treatment to the Cause
Each pattern points to a different first step. Mechanical and deconditioning pain responds best to a graded strengthening plan built with a physiotherapist, typically hip hinge practice, loaded carries, light deadlifts and daily walking, progressed over 8 to 12 weeks. Inflammatory pain needs a rheumatology referral and targeted medication rather than more core work. Stenosis often improves with flexion-based exercise, and in persistent cases with an epidural injection or decompression surgery.
What helps across nearly all seven is unglamorous and consistent: sleep seven to nine hours, keep moving at a level the pain allows, load the spine instead of guarding it, and rebuild capacity slowly. Progress is rarely linear, and flare-ups in week three don’t mean the plan has failed. Muscle and bone simply don’t remodel in a weekend.
Start by working out which of the seven patterns sounds most like yours, then take that description to a clinician who can examine you properly. A specific answer beats a generic one every time.
