I took chantix to quit smoking about 3 yrs. ago and I noticed a pain in a tiny area of my left breast, I was on Chantix for 3 weeks, got off of it and then started smoking again....I can still pin point the very spot I started feeling it in, and now it's getting worse, stronger charlie horse type pains on the top of my left breast and it's spreading to the upper left side of my breast now. I can feel it right now and it is really starting to worry me, what do you suggest I do?