Joint pain at the back of the arm is considered to be a disease of the shoulder joint, possibly frozen shoulder, which is usually seen in patients over 50 years of age. It is often characterized by pain in the shoulder joint as well as limitation of movement in all directions throughout the shoulder joint, with the pain being more pronounced at night. It may also be biceps tendonitis or shoulder impingement syndrome, which can also cause pain in the back of the arm when moving. There may also be rotator cuff injuries, inflammatory lesions of the shoulder joint, or infectious or neoplastic lesions of the shoulder joint. Causes other than the shoulder joint cannot be ruled out, such as cervical spondylosis, which may cause pain in the shoulder due to compression of the nerve roots. There may also be gallbladder or heart diseases that cause radiating pain throughout the back of the arm as well as the shoulder joint. All in all, it is recommended that the patient should go to a regular hospital for a complete examination to clarify the cause of the disease before further treatment.