Fibromyalgia produces a distinct type of pain that doesn’t come from damaged tissue or injured nerves. Instead, it’s caused by changes in how the nervous system processes pain signals, creating widespread discomfort that can feel like deep aching, burning, stabbing, or throbbing, often shifting in location and intensity. In 2017, the International Association for the Study of Pain formally classified this kind of pain as “nociplastic,” a third category alongside the two types most people are familiar with: pain from tissue injury and pain from nerve damage.
A Third Category of Pain
Most pain falls into one of two buckets. The first is pain from physical damage, like a sprained ankle or a cut. Specialized nerve endings detect the injury and send a signal to the brain, which registers it as pain. The second is nerve pain, caused by damage to the nerves themselves, as in diabetes or shingles. Fibromyalgia doesn’t fit neatly into either category.
Nociplastic pain arises from altered processing within the nervous system itself. The pain pathways become hypersensitive, amplifying normal signals or even generating pain when no harmful stimulus is present. To qualify as nociplastic, pain must last longer than three months, spread across multiple body regions rather than staying in one spot, and include signs of heightened pain sensitivity that can’t be explained by tissue or nerve damage. Fibromyalgia meets all of these criteria.
How the Nervous System Amplifies Pain
In fibromyalgia, the central nervous system, meaning the spinal cord and brain, becomes dialed up in a way that magnifies incoming signals. Researchers call this central sensitization. Repeated activation of pain-sensing nerves can lead to a kind of “wind-up” effect, where the spinal cord begins responding more aggressively to each successive signal. Over time, this creates long-lasting changes in how the brain interprets sensory information. The result is that stimuli which wouldn’t bother most people, like light pressure or a cool breeze, can register as genuinely painful.
Chemical imbalances play a role too. People with fibromyalgia tend to have elevated levels of substance P in the fluid surrounding the spinal cord. Substance P is a chemical messenger involved in transmitting pain signals, and higher concentrations mean louder signals reaching the brain. Glutamate, another chemical that helps nerve cells communicate, is also implicated. In fibromyalgia patients, levels of glutamate-related compounds in spinal fluid correlate with pain intensity, meaning higher levels tend to go hand in hand with worse symptoms. At the same time, the brain’s built-in pain-dampening pathways, which normally help dial down discomfort, appear to function less effectively.
What Fibromyalgia Pain Feels Like
People with fibromyalgia describe their pain in many ways, and it often changes character from day to day. A deep, persistent ache across the muscles is the most common description, sometimes compared to the soreness you’d feel after intense exercise that never goes away. Others report burning, prickling, or stabbing sensations. The pain tends to be widespread rather than localized, often affecting both sides of the body and areas above and below the waist.
Two specific pain phenomena are particularly common. The first is hyperalgesia, where something that would normally cause mild discomfort, like bumping your elbow, causes disproportionately intense pain. The second is allodynia, where things that shouldn’t hurt at all actually do. A light touch on the arm, the pressure of clothing on skin, or even a gentle hug can produce real pain. These aren’t imagined sensations. They reflect measurable changes in how the nervous system is processing input.
Pain intensity tends to fluctuate. Many people experience relatively manageable baseline pain punctuated by flares, periods where the pain spikes and becomes much harder to cope with. Flares can last days or weeks.
Common Triggers for Pain Flares
Fibromyalgia often first appears after a significant physical or emotional event. A serious injury, a major surgery, an infection like Epstein-Barr virus, or significant emotional trauma such as military combat can all precede the onset of symptoms. In some cases, the condition develops gradually with no obvious trigger at all.
Once fibromyalgia is established, day-to-day flares tend to follow patterns. Physical overexertion is one of the most reliable triggers, especially activities that push beyond your current tolerance. Emotional stress is another. Poor or disrupted sleep, weather changes (particularly cold or damp conditions), and hormonal fluctuations can also intensify pain. Learning your personal trigger patterns is one of the most useful things you can do for managing the condition, because it allows you to pace activities and prepare for difficult stretches.
Pain Is Only Part of the Picture
While pain is the defining feature, fibromyalgia rarely shows up alone. Fatigue is nearly universal, and it’s not ordinary tiredness. People with fibromyalgia often wake unrefreshed after long stretches of sleep, partly because the condition disrupts sleep architecture. Restless legs syndrome and sleep apnea are both more common in this population.
Cognitive difficulties, widely known as “fibro fog,” make it harder to concentrate, follow conversations, or hold onto short-term memories. Headaches, jaw pain from temporomandibular joint problems, and irritable bowel syndrome frequently overlap with fibromyalgia. Anxiety and depression are also common, which makes sense given that many of the same neurotransmitter imbalances involved in pain processing also regulate mood.
How Fibromyalgia Is Diagnosed
There’s no blood test or imaging scan that confirms fibromyalgia. Diagnosis relies on a clinical assessment using criteria developed by the American College of Rheumatology. Doctors evaluate two things: how widespread your pain is (scored on a 19-area body map called the Widespread Pain Index) and how severe your other symptoms are (rated on a Symptom Severity Scale covering fatigue, unrefreshing sleep, and cognitive problems). A score of 7 or higher on the pain index combined with a symptom severity score of 5 or higher meets the threshold, as does a pain index of 4 to 6 paired with a symptom severity score of 9 or higher.
The diagnosis also requires that symptoms have been present for at least three months and aren’t better explained by another condition. This often means ruling out autoimmune diseases, thyroid disorders, and other conditions that can mimic fibromyalgia. Women make up roughly 9 out of 10 diagnosed cases, though some researchers believe the gap may partly reflect differences in how men and women report symptoms and seek care.
What Pain Management Looks Like
Because fibromyalgia pain originates in the nervous system rather than in damaged tissue, standard painkillers like ibuprofen or acetaminophen generally don’t help much. Three medications are specifically approved for fibromyalgia, and they work by targeting nerve signaling rather than inflammation. One reduces pain by up to about 25% while also improving sleep and fatigue. That number is worth noting: a quarter reduction in pain is considered a meaningful improvement, but it highlights that medication alone rarely eliminates symptoms.
Exercise is consistently one of the most effective interventions, even though it can feel counterintuitive when movement hurts. Low-impact activities like walking, swimming, or gentle yoga gradually help recalibrate the nervous system’s sensitivity over time. The key is starting well below your pain threshold and increasing very slowly. Cognitive behavioral therapy has strong evidence for helping people manage the emotional and psychological dimensions of chronic pain, which in turn can reduce pain intensity itself. Sleep improvement strategies also matter, since poor sleep directly worsens pain sensitivity.
Most people with fibromyalgia find that a combination of approaches, rather than any single treatment, gives them the best results. The pain may not disappear entirely, but for many people it becomes manageable enough to reclaim significant quality of life.