Common causes of persistent arm pain include myofasciitis, cervical spondylosis, and osteosarcoma. 1. Myofasciitis: persistent pain in the arm may occur when the muscles of the arm undergo excessive labor, exercise, etc., leading to aseptic inflammation. 2. Cervical spondylosis: Due to cold or exertion, resulting in cervical spondylosis attack, the cervical nerve root is compressed or stimulated, causing persistent pain in the arm. 3. Osteosarcoma: Osteosarcoma originated in the upper limb, the tumor tissue invades and destroys the bone cortex, stimulates the periosteal nerve endings, and causes persistent pain in the arm. There may be other causes of persistent arm pain, such as osteoporosis, frozen shoulder, peripheral neuropathy, etc. It is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, and carry out standardized treatment under the guidance of the doctor.