Fibromyalgia pain is widespread, persistent, and comes in many forms at once. People with the condition describe it as a deep aching that never fully goes away, layered with episodes of burning, stabbing, and electric-shock sensations that can flare without warning. Unlike pain from an injury that stays in one spot, fibromyalgia pain spans both sides of the body, above and below the waist, and often shifts location from day to day.
How People Describe the Pain
One of the most striking things about fibromyalgia is how differently people experience it, yet how consistently they reach for extreme metaphors to explain it. In an FDA listening session where patients described their symptoms in their own words, the language was vivid: “electrifying,” “deep bone-aching,” “bee stings,” “pins and needles.” One person said it felt like knives sticking into their body whenever someone simply walked across the floor nearby. Another described feet that burned as if being bitten by thousands of fire ants.
The pain isn’t just one sensation. It tends to layer several types on top of each other. There’s a baseline of persistent muscle fatigue and soreness, like the heavy, leaden feeling you’d get after extreme overexertion. On top of that, people report burning pain from ordinary activities. One patient described getting the kind of muscle burn you’d feel during intense exercise just from standing up and walking to the kitchen. Muscle spasms add another dimension: a feeling of muscles contracting and refusing to let go. And during flares, a deep grinding sensation can set in, as if someone is kneading the muscles with force.
Stiffness is a near-universal feature. People describe being unable to rotate, stretch, or bend without intense discomfort. One person said climbing a few stairs was agonizing because their leg muscles felt so stiff and weak that they seemed on the verge of tearing. Headaches are also common and can be severe. One patient described a constant headache that felt like wearing a mold of your head that’s a quarter inch too small all the way around, creating an unrelenting crushing pressure.
Why Ordinary Touch Can Hurt
Many people with fibromyalgia experience pain from things that shouldn’t hurt at all. A light touch, a waistband, the pressure of leaning against a chair, even a breeze on the skin can register as painful. This happens because the central nervous system has become oversensitized. In fibromyalgia, the brain and spinal cord amplify incoming signals, turning mild sensations into pain signals and moderate pain into severe pain.
The mechanism behind this involves a chemical imbalance in the spinal cord and brain. Levels of the signaling molecules that transmit and amplify pain are elevated, in some cases up to three times higher than normal. At the same time, the brain’s natural pain-dampening systems are weakened. The chemicals responsible for dialing down pain signals are reduced, while the ones that ramp them up are overactive. The result is a nervous system stuck with the volume turned too high: more signals getting through, fewer being filtered out. This is why fibromyalgia pain feels disproportionate to what’s actually happening in the body’s tissues.
Where the Pain Shows Up
Fibromyalgia pain is defined by how widespread it is. To meet current diagnostic criteria, pain must be present in at least four of five body regions and must have persisted at a similar level for at least three months. The five regions include both sides of the body, the upper and lower halves, and the spine. In practice, this means the pain doesn’t stay in one predictable location. It’s bilateral, meaning it affects the left and right sides, and it can migrate. You might wake up with your shoulders and neck screaming, then find by afternoon that the worst pain has settled into your hips and legs.
Certain spots on the body are particularly tender. The original diagnostic guidelines identified 18 specific tender points, areas like the base of the skull, the tops of the shoulders, the outer elbows, the upper chest, the hips, and the inner knees, where even moderate finger pressure produces significant pain. While clinicians no longer require a formal tender point count for diagnosis, those areas remain reliably sensitive for most people with the condition.
What Triggers Flares
Fibromyalgia pain isn’t constant at the same intensity. It fluctuates between a manageable baseline and periods called flares, where symptoms spike dramatically. Several categories of triggers are well documented.
- Physical stress: Illness, injury, surgery, or even moderate physical overexertion can set off a flare that lasts days or weeks.
- Emotional stress: Anxiety, depression, and acute psychological stress are among the most potent triggers. Chronic stress from life disruptions, including events like the COVID-19 pandemic, has been shown to increase symptom severity across large groups of patients.
- Poor sleep: This is both a symptom and a trigger, creating a vicious cycle. More on this below.
- Weather and environmental changes: Many patients report that cold, damp weather or barometric pressure shifts worsen their pain, though this varies from person to person.
The Sleep-Pain Cycle
Sleep disruption isn’t just a side effect of fibromyalgia. It actively makes the pain worse. Research going back decades has shown that when you interrupt deep sleep (specifically slow-wave sleep) in healthy people, they develop fibromyalgia-like symptoms: widespread aching, fatigue, and heightened sensitivity to pressure. When normal sleep resumes, pain thresholds return to normal.
Deep sleep plays a critical role in resetting the nervous system, essentially dialing down the synaptic connections that built up during the day. When that reset doesn’t happen, the nervous system stays in a state of heightened excitability, the same central sensitization that drives fibromyalgia pain. Sleep deprivation also impairs the body’s ability to engage its natural pain-suppression systems. For people who already have fibromyalgia, a bad night of sleep can lower pain thresholds even further, making the next day’s pain significantly worse, which in turn makes the following night’s sleep harder to achieve.
Fibro Fog and Cognitive Effects
Pain in fibromyalgia doesn’t just hurt. It competes with the brain’s ability to think clearly. The cognitive difficulties that patients call “fibro fog” include problems with memory, concentration, and processing speed. This isn’t simply a matter of being distracted by pain, though that’s part of it. Brain imaging studies show that the areas of the brain involved in pain processing are overactive in fibromyalgia, consuming neural resources that would otherwise be available for thinking, planning, and paying attention.
Studies measuring cognitive performance during pain stimulation found a direct, inverse relationship: the higher a person’s pain intensity, the worse they performed across every cognitive domain tested. Reaction times slowed, errors increased, and the brain showed patterns consistent with attention being pulled toward pain and away from the task at hand. People with fibromyalgia also showed a higher threshold for distinguishing between two separate touch sensations, suggesting that pain processing is literally crowding out the brain’s ability to interpret other sensory information accurately.
Conditions That Often Overlap
Fibromyalgia rarely travels alone. About half of people with the condition also have irritable bowel syndrome, and roughly half experience chronic migraines. Chronic fatigue syndrome overlaps in about 51% of cases. Temporomandibular joint disorder (jaw pain) is even more common, appearing in roughly 64% of fibromyalgia patients. Depression and panic disorder also occur at high rates. These aren’t coincidences. They share underlying mechanisms, particularly the same kind of central nervous system sensitization that amplifies pain signals. If you have fibromyalgia and also deal with chronic digestive issues, jaw pain, or migraines, the connection is likely rooted in how your nervous system processes all types of signals, not just pain.
What Makes It Different From Other Pain
The feature that most distinguishes fibromyalgia pain from other chronic pain conditions is that there’s no visible tissue damage driving it. An X-ray, MRI, or blood test won’t show inflammation or structural problems in the areas that hurt. The pain is real, but it’s generated and maintained by changes in the central nervous system rather than by ongoing damage at the site where you feel it. This is why it’s classified as a centralized pain condition.
That distinction matters practically. Treatments that work for inflammatory pain, like anti-inflammatory medications, tend to be less effective for fibromyalgia because they target tissue inflammation that isn’t the primary problem. Approaches that address the nervous system’s sensitivity, including exercise, sleep improvement, stress management, and certain medications that modify how pain signals are processed in the brain and spinal cord, tend to be more helpful. Understanding that the pain comes from an amplified nervous system rather than from damaged muscles or joints doesn’t make it less real, but it does change how it’s best managed.