The common causes of swelling and pain in the lower arm include the following: First, acute injuries, including strenuous exercise or direct blows of violence, strains, contusions, sprains, etc., can lead to local tissue bleeding and hematoma formation, and at the same time can produce an acute inflammatory response, resulting in corresponding swelling and pain symptoms. Secondly, it is seen in chronic strain injury, which is common in people who often work on the upper limbs, such as construction workers, porters, road construction workers, etc., which can lead to corresponding chronic injury on the anterior wall, resulting in aseptic inflammation and long-term irritation to produce corresponding swelling and pain symptoms. Thirdly, it can be seen in local tumors, including muscle tumors and bone tumors, which can destroy the tissues and produce corresponding swelling and pain symptoms, so it is recommended that patients go to the hospital for examination and make corresponding intervention after clear diagnosis.