Hello, this is Dr. E. Greetings from New York! I'm so glad you posted your question for me to answer, and I aim to provide you with accurate info.
This sounds like tendonitis, which is a type of musculoskeletal pain usually due to overuse. I'm recommending that you do not use the arm for any lifting, that you rest it, apply ice to the most painful spot alternating with heating pad, and also that you keep it propped up on a pillow at night when sleeping. Start taking ibuprofen 600 mg every 6 hours with food for pain.