Sudden shoulder pain may be caused by physiological phenomenon, cervical spondylosis, frozen shoulder and so on. 1. Physiological phenomenon: If you don’t pay attention to keep warm after the weather change, the shoulder joint will be cold, and the muscle spasm around the shoulder joint can cause pain, or overwork, the accumulation of muscle lactic acid can also cause pain, which is a normal phenomenon. 2. Frozen shoulder: Chronic inflammation of the shoulder joint and surrounding tissues due to long-term over-exercise, trauma, chronic strain, etc. can cause pain in the shoulder joint, which is often accompanied by difficulty in lifting the shoulder joint, weakness and other symptoms. 3. Cervical spondylosis: due to improper posture, long-term head down playing cell phone, etc., leading to degenerative changes in the cervical spine, nerve root compression, can cause pain, numbness and other symptoms of the shoulder joint. Shoulder pain is caused by more reasons, may also be related to trauma, coronary heart disease, rotator cuff injury, biceps long head tendonitis and other diseases, if the symptoms continue to be unrelieved, it is recommended to consult a doctor in time, to clarify the cause of the disease, and to carry out targeted treatment.