Always tendon pain in the arm is considered to be caused by muscle injury, tendonitis, myofasciitis and other reasons. 1. Muscle injury: If you haven’t played sports for a long time, suddenly play a lot of sports or play sports in an improper posture, resulting in local muscle or tendon injuries, it may lead to the symptom of arm always tendon pain. 2. Tendonitis: when suffering from tendonitis, the tendon area will secrete a lot of inflammatory factors, when the inflammatory factors stimulate the local nerve tissue, it will cause the symptom of arm always tendon pain. 3. Myofasciitis: when suffering from myofasciitis, the patient’s fascial tissues will be seriously damaged and blood vessels are compressed, resulting in local metabolic disorders, so that the local histamine and kinin components abnormally high, which will appear in the arm always tendon pain symptoms. Because of the causes of the arm always tendon pain more causes, it is recommended to go to the hospital in time for examination and diagnosis, to clarify the cause of the disease, under the guidance of professional physicians to carry out targeted treatment, so as to avoid aggravation of the condition.