I've been getting a sharp pain under my left breast which causes me not to breath properly due to the sharpness feeling like its moving across my ribs?

Costochondritis: You could have a muscle strain or costochondritis. I would try Ibuprofen tid initially.

Chest Pain: Your symptoms are always worrisome. Of course we worry about heart problems, lung problems like pneumonia, pleurisy, and pulmonary emboli, and of course chest wall pain. Please see a physician to further clarify your health problems.