What is causing constant arm pain?

Arm pain: Pain with arm movement is likely the arm/shoulder. Pain with neck movement suggests nerve pain from a herniated disc. Neither urgent if not progressing. Ok to try some nsaids, ice/heat for a couple days. Typically, these usually improve over several weeks. Pain that does not deserves a doc evaluation.

ARM PAIN: Arm pain can originate from many sources. Is the pain starts in the neck and radiates down the arm, it is probable a result of a nerve being impinged as in the case of a cervical herniated disc with radiculopathy. This should be checked by a physician if it doesn't subside quickly. A physiatrist who specializes in musculoskeletal medicine would be a smart choice. Good luck.