Yesterday my upper left back felt really tight then i felt it crack and there was a loud squelching sound and now i'm in agony can anyone help please?

See a doctor: If you are having severe back pain, numbness, weakness or loss of bowel or bladder control, you need to see a physician immediately.

Emergency room: This doesn't sound like anything typical, especially in the absence of any trauma, so if you are in agony i would go into the er or at least call your primary physician and have them evaluate you.