Back pain

I don't know if anyone could help or suggest something for me. I am a 36DDD, and i constantly have back pains. At times if i don't lay on my back for a bit, i start feeling like i can't breath, i start to feel light headed. Not until i rest my back i feel a little better. And other times if feels like a stabbing feeling in the front of my chest and just really bad.back pain..any one have any suggestions?