Upper arm muscle pain should be alert to muscle strain, cervical spondylosis, heart disease and so on. 1. Muscle strain: it is mainly caused by the prolonged fatigue compensation of muscles. Prolonged fatigue compensation of the muscle, there will be edema, increased exudation, stimulation of the nerve root leading to pain. 2. Cervical spondylosis: cervical spondylosis is mainly due to degenerative lesions of the cervical intervertebral disc. When the cervical spine is active, the proliferated bone or intervertebral disc may stimulate the nerve root, resulting in radiating pain in the muscles of the upper arm, and in severe cases, numbness, weakness or even atrophy of the muscles of the upper arm may occur. 3. Heart disease: heart disease causes upper arm muscle pain mainly due to myocardial ischemia. Myocardial ischemia will cause anaerobic metabolism of the myocardium, producing lactic acid, stimulating the visceral nerves, the pathway responsible for transmitting visceral nerve sensation to the cerebral cortex and the corresponding sensory nerves innervating the upper arm muscles share the same spinal cord segments, which will be manifested as pain in the upper arm muscles, which is also known as radiating pain in the clinic. If the symptoms of upper arm muscle pain are severe, or if the symptoms do not improve, the patient should go to the hospital in time for treatment.