Faced with diffuse pain, the doctor must evoke a wide range of pathologies. It is necessary to think about rare illnesses such as myopathy or vasculitis, but also more common illnesses such as fibromyalgia. Contrary to popular belief, it is difficult to give a diagnosis of fibromyalgia, on average 2 years after the onset of symptoms. This can be explained by heterogeneous complaints and the doctor delaying the diagnosis with unnecessary complimentary examinations.Patient education and physical activity are the most important steps of treatment. Few drugs have proven effective and their use is limited due to significant side effects. The evolution of fibromyalgia is chronic, with a mixed prognosis.