Extreme back pain... should I see a doctor?

I always have back pain, I have very large breasts. But lately it's been extremly worse like my spine feels like it's been punched. I get no relief from tylonel or motrin and laying down doesn't help. It's actaully painful to breathe at times (not 24/7 just randomly it will be difficult for a few minutes) I haven't done anything to cause increased pain. So what may this be and should I see a doctor?