The exact cause of fibromyalgia is unknown, but it's thought to be related to abnormal levels of certain chemicals in the brain and changes in the way the central nervous system (brain, spinal cord and nerves) processes pain messages carried around the body. It's also suggested that some people are more likely to develop fibromyalgia because of genes inherited from their parents. In many cases, the condition appears to be triggered by a physically or emotionally stressful event, such as: an injury or infection giving birth having an operation the breakdown of a relationship the death of a loved one