If the patient has a symptom of shoulder pain, it may be related to the following causes: 1. There may be frozen shoulder on one side, which is the most common in clinic. If the patient’s shoulder is cold or has old trauma, it may lead to aseptic inflammation inside the shoulder joint, which in turn leads to exudate around the joint, and at this time, the joint may have pain and very obvious limitation of activities. 2, there may be an injury to one side of the shoulder joint. When the patient is squeezed or pulled by the shoulder joint inadvertently, the joint capsule or the ligaments inside the shoulder joint may be damaged, which may make the patient feel the pain in one side of the shoulder.3, there may be other inflammatory diseases of the shoulder joint. Gouty arthritis or rheumatoid rheumatoid arthritis may involve the shoulder joint and cause pain in the shoulder joint. This is most common during an attack of gouty arthritis. Because this type of arthritis tends to involve a single joint, it is easy to experience shoulder pain on one side.