Fibromyalgia is a chronic pain condition in which the brain and nervous system process pain differently. This altered pain perception is called central sensitization, meaning that nerve cells in the brain and spinal cord become more sensitive and amplify pain signals.

At the same time, the body’s natural pain-relief systems work less effectively in people with fibromyalgia, which increases the perception of pain. Normally, pain serves as a warning signal of injury or illness, but in fibromyalgia, the pain is not caused by direct damage to muscles, joints, or organs. Instead, the pain system itself is “reprogrammed” and reacts excessively.

Fibromyalgia typically presents as persistent, widespread pain in muscles, tendons, and joints that can move around the body and vary in intensity from day to day. Many also experience pronounced fatigue that can feel overwhelming even with minor physical activity. The word fibromyalgia literally means “pain in muscles and tendons.”

For many, the pain begins in one area and gradually spreads to other parts of the body. The condition is classified as a generalized pain disorder because the pain can occur in nearly all tissues and affect muscles, tendons, and joints.

Fibromyalgia can affect anyone – children, adolescents, adults, and the elderly – and can occur in people who already have other medical conditions. However, it is far more common in women, who make up about 75–90% of those diagnosed with fibromyalgia.