Back Pain/ Breathing Problems

I am only 19 years old, and I have had this problem since I was probably 15. When this gets to its worst I have intense pain in my middle back. I have a hard time standing up straight, but when I do stand up straight I can breath fine. When I inhale deeply it feels as if my lungs are pressing against my rib cage. If I bend over to pick something up I have a mildly uncomfortable feeling in my upper back, as if muscles were rubbing against something. When I lie down on my side, it will feel like my heart is against my rib cage, and you can hear a pumping noise. This noise is not normal. It sounds like something is putting pressure on my heart, and causing it to have a hard time pumping. I have gone to a chiropractor. I explained to him what was going on, and he said that it is nothing big. He said that I have just picked something up and twisted my back, and it has thrown my spine out. Therefore the pain I feel in my muscles is them being out of their normal position, and being sore. After about two to four(and close to $100) adjustments I am back to normal and feeling perfect again. I am leaving for the marines feb. 3rd. And I am just getting over this little deal again, I have been once to my chiropractor and am feeling fine. But when I went to run today, only my right side of my back started to get tense. Putting pressure on my lungs, and making it hard to breathe.

If I could get any help, I would appreciate it.