The causes of right upper arm muscle pain, including muscle injury, rotator cuff tear and acromion impingement syndrome, are as follows: First, muscle injury: acute injury to the right upper arm muscles can occur during strenuous exercise, thus causing muscle pain, swelling and limitation of upper extremity activities, with significant pain when pressed and a significant increase in local skin temperature, and the patient has a clear history of trauma. Second, rotator cuff tears and impingement syndrome: Patients with rotator cuff tears and impingement syndrome can induce painful symptoms in the lateral muscles of the right upper arm, accompanied by shoulder pain and limited movement of the shoulder joint, and the muscle strength of the right upper limb will be significantly reduced, affecting the patient’s normal life, work and sports. Timely use of arthroscopic minimally invasive surgery can restore the tendon injury and also remove the hyperplastic shoulder crest, relieving the symptoms of right upper arm muscle pain.