I have been on birth control pills for 3 months now. My boyfriend and I have started to have sex without a condom to start out and then we finish with a condom. I am on the 2nd week of my pills - I haven't missed any pills - but my breasts have been sore for the past 3 days. We don't see each other often, so when we do have sex it is usually intense and long. Could this be the reason my breasts are sore?