Having unbearable pain only in the right arm. My mom has been developing pain in her right arm for the past few weeks and seems that it's up to a point where she can't straighten her arm. She said her entire right side of her body is sore but not as painf

She . She should see her primary care provider. If she does not have one she can seek out a family medicine doctor or internist (internal medicine). A detailed history and physical will need to be done in order to come up with possible diagnoses. Tests will then be done to confirm or exclude the possibilities. Just based on your post, it sounds like she may be dealing with musculoskeletal pain, a gout attack, or even a viral illness. It is very difficult to say at this point. If she is having any chest pain, palpitations, neurological deficits (slurred speech, weakness, etc) she should present to the emergenct room. Best of luck, .
This . This sounds like a relatively serious problem that should be evaluated sooner rather than later. A primary care doctor would be a relatively good area to start, as well as a physiatrist (physical medicine) doctor or a surgeon.