Pain in the right upper arm occurs for several common reasons: 1. Rotator cuff injury. Rotator cuff damage can occur when the rotator cuff tissue is worn down by the acromion, even leading to tears. The local pain can be radiated to the right upper arm lateral and deltoid dominant area, and the patient will also have obvious shoulder joint weakness, limited forward flexion and abduction. 2. Shoulder trauma. 3.Cervical spondylosis, nerve root type cervical spondylosis can lead to radioactive pain in the innervation area of the right upper arm, and can be accompanied by clinical manifestations such as neck pain and limitation of cervical movement.