Your Pain Is Real. Your Scans Are Clear. Here’s What’s Actually Going On.
When chronic pain persists without a clear structural cause, your nervous system might be the missing piece of the puzzle.
You’ve had the scans. The bloods. Maybe even an MRI or two. Everything comes back “normal.” And yet the pain is very much still there — in your back, your neck, your jaw, your shoulders, your gut. It moves around. It flares unpredictably. It doesn’t match what the imaging shows.
So you start wondering if it’s in your head. Or worse, someone implies it.
It’s not in your head. But it might be in your nervous system. And that distinction matters, because it changes what you do about it.
There’s a growing body of research showing that chronic pain — particularly pain that persists beyond what tissue damage would explain — is often driven by changes in how your central nervous system processes pain signals. Your brain and spinal cord become hypersensitive. Signals that shouldn’t register as painful start to. And signals that are mildly uncomfortable get amplified into something much worse.
This isn’t a psychological problem. It’s a neurophysiological one. And it’s directly connected to the state of your nervous system.
Central sensitisation: when your alarm system gets stuck on high
In 2024, a review published in Current Medicinal Chemistry described central sensitisation as an increased responsiveness of pain-processing neurons in the central nervous system to normal or even below-threshold input. In plain language: your nervous system starts overreacting to signals that wouldn’t normally cause pain, or dramatically amplifying pain signals that should be mild.
This isn’t a niche concept. Research published in The Lancet Rheumatology found that features of central sensitisation have been documented across a wide range of pain conditions — fibromyalgia, osteoarthritis, rheumatoid arthritis, chronic low back pain, headaches, tendinopathies, and spinal pain. Within each of these conditions, there’s significant variation between patients in how much central sensitisation is present, which is why two people with the same diagnosis can have completely different pain experiences.
Here’s what this means practically: the amount of pain you feel often doesn’t correlate with the amount of tissue damage. This has been one of the most confusing aspects of chronic pain for both patients and clinicians. Someone with a relatively minor disc bulge can be in agony, while someone with significant structural changes can have minimal symptoms. Central sensitisation helps explain why.
The International Association for the Study of Pain introduced the term “nociplastic pain” in 2017 to describe this third category of pain — distinct from nociceptive pain (caused by tissue damage) and neuropathic pain (caused by nerve damage). Nociplastic pain arises from altered pain processing in the central nervous system, and its symptoms often include not just pain but also fatigue, sleep problems, brain fog, and mood disturbance. If that list sounds familiar, it should. Those are also the hallmark symptoms of nervous system dysregulation.
The stress–pain connection is bidirectional
Chronic stress doesn’t just make you feel tense. It physically changes how your nervous system processes pain.
When your HPA axis is chronically activated — pumping out cortisol in response to ongoing stressors — it creates a cascade of effects that directly feed into pain sensitisation. Elevated cortisol promotes neuroinflammation through the activation of glial cells (the immune cells of your central nervous system). These activated glial cells release inflammatory cytokines that sensitise pain pathways, lower pain thresholds, and maintain the kind of central nervous system hyperexcitability that keeps pain going long after the original trigger has resolved.
Research published in Frontiers in Psychiatry found that chronic stress disrupts the blood–brain barrier, allows inflammatory mediators to cross into the central nervous system, and activates microglial cells that then perpetuate the inflammatory cycle. This creates what researchers describe as a self-reinforcing loop: stress drives inflammation, inflammation sensitises pain pathways, pain itself becomes a stressor, and the cycle continues.
A review in Neurology: Neuroimmunology & Neuroinflammation described microglia as “central protagonists in the chronic stress response” — highlighting that repeated stress exposure changes the phenotype and function of these brain immune cells in ways that sustain neuroinflammation. This isn’t temporary. These are structural and functional changes in the central nervous system that persist even after the original stressor has passed.
And here’s what ties it back to your lived experience: if you’ve been running on cortisol fumes for months or years — managing a demanding career, chronic sleep debt, relational stress, caregiving responsibilities — your nervous system has been marinating in the exact neurochemical conditions that promote pain sensitisation. The pain isn’t separate from the stress. They’re the same system.
Why your nervous system state matters more than your scan results
A key insight from polyvagal theory and from the chronic pain research is that your autonomic nervous system state directly influences your pain experience.
Research on fibromyalgia — one of the most studied nociplastic pain conditions — has consistently found reduced vagal tone (as measured by heart rate variability) in people with the condition. A review published in Neuroscience & Biobehavioral Reviews examined fibromyalgia through the polyvagal theory lens and described how autonomic dysfunction, specifically reduced ventral vagal activity and sympathetic dominance, is implicated not just in pain but in the full cluster of fibromyalgia symptoms: pain, fatigue, sleep disturbance, cognitive problems, and emotional dysregulation.
The same autonomic imbalance has been documented in irritable bowel syndrome, chronic headache, interstitial cystitis, and endometriosis. Research published in PMC proposed that these conditions share a common pathophysiology rooted in chronic autonomic threat responses — specifically, a nervous system that’s stuck in protective mode, with dampened ventral vagal function and elevated sympathetic or dorsal vagal activity.
In other words, the same nervous system dysregulation that makes you feel wired and exhausted, that stops you sleeping properly, that makes you reactive in meetings and flat on the couch by Friday evening — that same dysregulation is amplifying your pain signals. Your pain and your burnout aren’t separate problems. They’re both expressions of a nervous system running in survival mode.
The conditions that keep showing up
If central sensitisation and nervous system dysregulation are driving your pain, you’re likely dealing with one or more of these patterns. Not because they’re “all in your head,” but because they’re all expressions of the same underlying neurophysiology.
Persistent back or neck pain that doesn’t match imaging findings. Tension headaches or migraines that flare with stress. Jaw pain and teeth grinding that your dentist keeps flagging. Fibromyalgia or widespread pain with fatigue. IBS or gut symptoms that worsen under pressure. Chronic pelvic pain. Pain that moves around your body, never quite settling in one place.
The common thread isn’t the location. It’s the system. A 2024 review in Neuroscience & Biobehavioral Reviews noted that researchers are still debating whether central sensitisation causes chronic pain or is a consequence of it. The honest answer is: the relationship is complex and likely bidirectional. But what’s clear from the evidence is that the state of your central nervous system — how sensitised it is, how much neuroinflammation is present, how your autonomic nervous system is regulated — plays a significant role in whether pain persists, how intense it is, and how much it disrupts your life.
What doesn’t work (and what does)
If your pain has a significant central sensitisation component, then interventions focused exclusively on the peripheral site of pain — more injections, more scans, more surgeries targeting a structural “pain generator” — may not address the actual problem. Research published in Current Medicinal Chemistry specifically noted that understanding central sensitisation can help avoid perseverance in pursuing procedures or surgeries when no reliable pain generator can be identified.
That doesn’t mean the pain isn’t real. It means the driver has shifted from peripheral tissue to central nervous system processing. And that requires a different approach.
What the research supports for reducing central sensitisation includes pain neuroscience education (understanding what’s actually driving your pain changes the brain’s response to it), graded movement and exercise that works with your nervous system’s current capacity rather than pushing through pain, stress reduction that actually addresses the physiological stress response rather than just telling you to relax, and approaches that target autonomic regulation directly.
A 2024 randomised clinical trial published in JAMA compared a modern pain neuroscience approach (combining pain education, stress management, and cognition-targeted exercise) against usual care physiotherapy for chronic whiplash-associated disorders — a condition strongly associated with central sensitisation. The approach that addressed the nervous system, not just the structural injury, showed better outcomes.
This is where nervous system regulation work becomes relevant. Not as a replacement for medical care, but as a missing layer. If your pain is being maintained by a nervous system stuck in threat mode, then helping that system shift out of chronic defence is not just complementary — it’s addressing one of the core mechanisms.
What this means for you
If you’ve been told your scans are clear but you’re still in pain, you’re not making it up and you’re not crazy. Your pain is real. It’s just that the source isn’t where everyone has been looking.
If your pain gets worse with stress, poor sleep, or emotional overwhelm — that’s not weakness, that’s your nervous system telling you exactly what’s driving the problem. Pain that fluctuates with your stress levels is pain that has a significant central component. That’s useful information, because it means addressing your nervous system isn’t a nice-to-have. It’s the intervention.
If you’re dealing with pain alongside fatigue, brain fog, sleep problems, and emotional reactivity — those aren’t five separate problems. That’s one dysregulated system showing up in multiple ways. And it requires a whole-system approach, not isolated fixes for each symptom.
Your body isn’t broken. Your nervous system is protecting you. The work is helping it learn that it can stop.
Genevieve Gray BHSc, C.Hyp, RTTP
Nervous System Educator & RTT® Practitioner