Most soft tissue injuries heal within weeks. So why do so many people still have pain months or years later? The answer has almost nothing to do with the original injury — and everything to do with what happens in the nervous system.
“When pain outlasts tissue healing, the problem is usually a sensitised nervous system — and that can be retrained.”
Tissue heals faster than you think
The body's repair capacity is genuinely impressive. A muscle strain typically heals in 2–6 weeks. Ligaments take a bit longer — 6–12 weeks for most. Even a herniated disc usually clears its inflammatory phase within 3 months.
So here's the puzzle: if tissue heals on that timeline, why are so many people still in pain at 6, 12, or 24 months after an injury? Something else is going on.
Central sensitisation: when the volume dial gets stuck
When pain hangs around long enough, the nervous system itself starts to change. This is central sensitisation — a state where the central nervous system becomes amplified in how it processes pain signals.
Clifford Woolf defined it as an amplification of neural signalling within the central nervous system that produces pain hypersensitivity. In plain terms: the nervous system turns up its own volume dial, and it gets stuck there.
This shows up a couple of ways. Allodynia means things that shouldn't hurt — light touch, gentle movement — start to hurt. Hyperalgesia means things that hurt a little start hurting a lot. The pain is real, but it's no longer being driven by tissue damage. It's a nervous system that has learned to be more sensitive.
Wind-up and the pain memory
Repeated stimulation of pain pathways produces something called wind-up — where each signal triggers a bigger response than the last. Think of a guitar string plucked repeatedly: the resonance builds.
Over time, the nervous system can develop what researchers describe as a "pain memory" — neural pathways that fire in patterns laid down during the original injury, long after the injury itself has resolved. The brain has essentially learned to produce pain in response to certain cues.
I want to be clear: this doesn't make the pain fake. It means the pain system itself has been changed by the experience of pain.
What keeps sensitisation going
Several things maintain a sensitised pain system. Ongoing stress and threat keeps the nervous system on alert. Poor sleep reduces the brain's ability to regulate pain signals. Catastrophic thinking — telling yourself something is seriously wrong — increases perceived threat. And persistent avoidance of movement deprives the brain of the safety signals it needs to settle down.
This is why chronic pain is never just a tissue problem. The people I see recover best are the ones who understand what's happening in their nervous system — and use that understanding to stop feeding the sensitisation loop.
References
- 1.Woolf CJ. (2011). Central sensitization: implications for the diagnosis and treatment of pain. Pain, 152(3 Suppl), S2–S15. PMID: 20961685.
- 2.Nijs J, Torres-Cueco R, van Wilgen CP, et al. (2014). Applying modern pain neuroscience in clinical practice: criteria for the classification of central sensitization pain. Pain Physician, 17(5), 447–457. PMID: 25247901.
- 3.Moseley GL & Flor H. (2012). Targeting cortical representations in the treatment of chronic pain. Neurorehabilitation and Neural Repair, 26(6), 646–652. PMID: 22331213.