Me too...since I was like 12. I was slightly overweight which I think was the cause and since building my chest up it decreases day by day. Another thing the helps is lowering body fat. If you're lean and have no extra pinch around your chest area, then chances are it might be a mild case of gyno do to a on-set of birth hormonal imbalance....this is just what my doc told me 7 years ago. Unless you have an ache, constant swelling even in cold temperatures or cold water, a noticeable lump behind either/both nipples, and/or some type of discharge from your nipple - all is well. I wouldn't worry. Even on my current cycle I've had no increase and actually a good decrease from more free test instead of estrogen (original hormonal imbalance).