Infection
Some forms of bacterial and viral infection might cause upper arm pain. After penetrating the body, they irritate or damage many areas of this part, such as the nerves, bones, and skin. Varicella zoster is a form of virus that would stay dormant in your peripheral nerves for many years. It would result in shingles, a blistering, itchy, and painful rash that usually occurs in immunocompromised people or the elderly. [3]
