Pain on the lower side of the arm may be caused by trauma, cervical spondylosis, frozen shoulder, osteophytes and so on. 1. trauma: if the upper body localization is accidentally sprained or strained, it may cause pain on the lower side of the arm. 2. Cervical spondylosis: If you suffer from cervical spondylosis, the nerve roots of the cervical vertebrae may be stimulated, which may lead to radiating pain on the lower side of the arm. 3. frozen shoulder: patients with frozen shoulder usually have symptoms of swelling and pain around the shoulder, especially when the shoulder area is moving, the pain will be especially obvious, so it may lead to pain on the lower side of the arm. 4. Osteomalacia: If the patient has osteomalacia in the arm, the ligaments around the ligament if there is damage, it will cause pain in the lower side of the arm. Lower arm pain may also be caused by other reasons, it is recommended that the patient needs to go to the hospital for relevant examinations, after clarifying the cause of the disease, under the guidance of the doctor to carry out the corresponding treatment, in order to alleviate the symptoms of pain as soon as possible.