If a patient has pain on the lateral side of the upper arm, the causes triggered are mainly external humeral epicondylitis, frozen shoulder, nerve root type cervical spondylosis, and muscle and fascia pulling or injury on the lateral side of the upper arm, as follows: 1. External humeral epicondylitis: The disease tends to cause significant pain and pressure on the lateral side of the upper arm. 2. Frozen shoulder: It also causes soreness and pain on the lateral side of the upper arm. 3. Nerve root type cervical spondylosis: The patient also 4. upper arm trauma: muscle and fascia strain or injury on the outer side of the upper arm can also easily cause symptoms of pain on the outer side of the upper arm. Therefore, patients with pain in the lateral upper arm must seek medical attention in a timely manner to identify the cause and then treat the cause in order to promote the reduction of pain symptoms and recovery. When the pain is obvious, it is important to avoid repeated shoulder lifting activities and excessive lifting of heavy objects on the upper limbs, which may lead to increased pain. When the pain is obvious, you can also apply non-steroidal anti-inflammatory drugs, together with blood circulation drugs to temporarily relieve the pain symptoms.