I have a bad pain in my back. It feels like its behind my lungs. Pain increases when I breathe. It makes me feel like I can't breathe and can't move.?

Evaluate. You are describing pleuritic pain. This could represent something serious and you should seek attention. Possibilities range from serious (pulmonary embolism -blood clot to lung, aortic dissection - tear in aorta, lung infection) to more benign condition such as musculoskeletal pain. Get evaluated if symptoms continue.