What could be the cause of violent muscle twitches all over and buzzing right upon waking from sleep? lasts for about 2-20 minutes. thanks~

Fibromyalgia (FM): Fm is reported to be the most frequent cause of chronic, widespread pain for which no other cause can be determined — there is no evidence of a systemic disorder. 90% of patients with fibromyalgia report poor sleep. The diagnosis of fm depends on a history of widespread tenderness, pronounced fatigue and sleep disturbance, and the presence of tender points.