Hi, I'm Dr.Nitika-a board certified physician. Welcome to JustAnswer. I'm reviewing your question now, and will post back with your reply ASAP.
I understand your discomfort.
As per your description,possibly it's a problem with your rotator cuff.
Other possible differential diagnosis may include Nerve compression,frozen shoulder,Arthritic degenerative changes in shoulder.
An orthopedic surgeon who specializes in shoulders can diagnose and treat properly.
Prompt treatment provides you good outcome.
Initially, the treatment is typically OTC Advil,warm compresses,gentle massage with topical diclofenac sodium ointment and physical therapy exercises. Steroid injections may also be helpful.
So see a doctor ASAP in next few days rather then wait.
Hope this helps.
Feel free for further queries. It's good to discuss rather than quit.
Your satisfaction is our goal.
We are here to help you until you satisfy.