In the past couple of days i've been having sharp pains in my middle upper back and today its kind of moved lower down but still in the middle.?

Intraspinal issue: The problem almost certainly resides in the spinal column, that system of bones, ligaments, tendons & the muscles which support them. Causes are varied from posturally induced muscle spasm to malignant bone tumors, herniated discs, inflammatory arthritis, etc. Your symptoms unfortunately are non-specific.

Muscle strain: Sounds like you may have pulled a muscle. I recommend getting into some physical therapy which may help. Anti-inflammatory medications may also help.