Arm pain feels like the tendons inside hurt and can’t be lifted may be caused by trauma, frozen shoulder, cervical spondylosis, arthritis, ankylosing spondylitis and so on. 1. Trauma: refers to ligament strain, fracture, rotator cuff injury, etc. When lifting the arm, it pulls the damaged muscles, bones or ligaments, resulting in tendon pain and restricted movement. 2. Frozen shoulder: mostly seen in people who operate computers for a long time, engage in heavy physical labor, or are of advanced age, which may cause adhesion of soft tissues of joints and weakening of muscle tension, resulting in pain in the tendons of the arm, inability to lift the arm, and soreness of the shoulder. 3. Cervical spondylosis: it can be caused by osteophytes, degenerative changes of cervical vertebrae, and the neck being in a wet and cold environment for a long time, etc. When it occurs, it compresses the nerves or blood vessels of the arms, and then there will be soreness in the neck and difficulty in rotating accompanied by tendon pain. 4. Arthritis: including osteoarthritis, gouty arthritis, rheumatoid arthritis, etc. Inflammatory mediators make the surrounding muscles, ligaments and other adhesions, and irritate the nerves, resulting in arm pain, inability to lift the arm, and redness and swelling of the joints. 5. Ankylosing spondylitis: it is a disease caused by family genetics, abnormal expression of immune factors, endocrine imbalance, etc. When it invades the spine, it may cause bilateral arm tendon pain, unable to lift up. There are many other reasons why you can’t lift your arms, so it is recommended that you go to the hospital and get a clear picture of the cause with the help of your doctor.