There are many reasons for the pain caused by stretching of the right shoulder, such as muscle strain, cervical spondylosis, frozen shoulder, osteoarthritis of the shoulder joint and so on. 1. Muscle strain: prolonged weight bearing on the right shoulder or lack of adequate preparation for right shoulder activities will lead to injury of local muscles and ligaments of the shoulder joint, resulting in aseptic inflammation and affecting the function of shoulder joint activities. 2. Cervical spondylosis: the nucleus pulposus of the cervical intervertebral disc protrudes into the annulus fibrosus, which compresses the soft tissues, blood vessels and nerves around the cervical spine. When the nerves innervating the right shoulder joint are compressed, it will cause pain in the right shoulder, thus affecting the movement of the joint. 3. Frozen shoulder: excessive movement of the right shoulder leads to inflammation of the joint capsule, muscles, ligaments and other soft tissues of the shoulder joint, and at the same time the gap between the joints becomes narrower, thus affecting the stretching of the shoulder and causing pain. 4. Osteoarthritis of the shoulder joint: the bony structures in the shoulder joint undergo hyperplasia and degeneration, which narrows the gap between the two bone surfaces and increases the friction, thus generating pain and accompanied by activity limitation. In conclusion, right shoulder stretching pain can be caused by a variety of reasons, in order to alleviate the symptoms as soon as possible, it is recommended that patients go to the orthopedic department of the hospital for consultation and treatment.