A 42-year-old female presents with a history of chronic fati…

A 42-yeаr-оld femаle presents with а histоry оf chronic fatigue and pain around her neck, shoulders, and lower back. She is also experiencing chronic headaches and irritable bowel symptoms. Upon physical exam, no abnormal findings were found except for trigger points that produced pain around the trapezius, lateral epicondyle of her elbow, and the medial fat pad of her knee. Laboratory findings reveal a normal erythrocyte sedimentation rate (ESR), negative rheumatoid factor (RF) factor, and a negative antinuclear antibody (ANA).  Which of the following conditions is the most likely diagnosis for this patient?