As such, suvorexant may provide unique clinical benefit as a treatment in chronic pain conditions with co-morbid insomnia, and specifically for fibromyalgia with its putative central hyperarousal and hypersensitization. Thus, this project proposes to study objective and clinical measures of sleep, pain, and daytime sleepiness and fatigue in patients with fibromyalgia and co-morbid insomnia while treated short-term with suvorexant 20 mg versus placebo.