When breathing deeply (yawning, sneezing, etc.)i feel sharp upper left back pain, also with sudden movements. Plus joint pains. What to do &what is it?

Student Back. If you sit during the day, certain muscles become tight and can cause these symptoms. There are also more serious things like gallbladder disease that causes this sort of pain. Most likely it's a strain. Seek out a good D.O. For diagnosis and treatment.
See Osteopathic Dr. These symptoms often found w/ vertebral or rib dysf.Ribs normally move up/down with inhaling/exhaling.If rib gets locked down (can't rise w/ inhaling) pain in back, usually near shoulder blade results-exacerbated by deep breath/yawn.Shoulder & other jts can be secondarily affected.A good history & phys incl hands-on osteopathic exam may find cause.Can often fix with gentle osteopathic manipulation.