How old are you? If you are a minor (under 18), tell your parents. But otherwise, while it is probably nothing, you should get that checked out. It can be a symptom of a cardiac issue. Remember, issues with the heart are not terribly common for young people. I don't know your age . . . so am just mentioning that. But radiating pain down one arm to elbow needs to be examined. It is MOST likely a pinched nerve as that is the way they run through that area. And exercise and ibuprofen, physical therapy if it is really bad will help. good luck
So, in all sincerity, if you live in the United States and work only part time due to your autism, can you apply for Medicaid? It's worth a try to get medical care. So, at least you got to the doctor and they must have ruled out heart issues which is good. I was wanting to make sure that isn't going on. What about looking up stretching exercises for that area? Gentle stretching. And a nonsteroidal anti inflammatory would be a good idea as it gives mild pain relief AND reduces swelling in the body. NSAIDs are a fancy word for things people find OTC such as alleve, naproxen, even ibuprofen at a max dose will be effective for that. You can ice the area as best you can. Those are things you can do on your own to see if they help. Pain relievers aren't terribly helpful to the injury other than to relieve your pain. Which has value but you need to be doing some things to help the source even if you don't fully know it. That's why nsaids are a good idea to help reduce swelling, stretching is essential, ice helps. Sometimes rolling on a tennis ball (put one under your shoulder blades and roll on it) can help like a mini massage. I hope you get relief soon!