Elbow pain may be caused by elbow bone syndrome, arthritis, humeral epicondylitis and other diseases. 1. Elbow bone syndrome: due to the long-term maintenance of poor posture, such as sleeping on the arm, resulting in ulnar nerve entrapment, elbow pain, may be accompanied by numbness of the little finger phenomenon. 2. Arthritis: senile arthritis or rheumatoid arthritis, degenerative joint disease can lead to joint swelling and pain. 3. Epicondylitis of the humerus: also known as tennis elbow, it is a chronic inflammation caused by the repeated wear and tear of the total tendon of the extensor muscles of the forearm on the lateral epicondyle of the humerus due to the repeated activities of the wrist joint. It is characterized by pain on the lateral side of the elbow joint, which is aggravated by clenching the fist or stretching the wrist. In addition to the above reasons, excessive activity, elbow trauma, malignant bone tumors, etc. can cause elbow pain, it is recommended that patients go to the hospital in a timely manner to find out the cause of the disease, under the guidance of the doctor to choose targeted treatment.