Nipple Soreness?

My are sore. Only when you touch them. They don't ache when I'm just sitting here and they're not sore all the time. I've been on Yasmin for 4 years. My period should be coming Wednesday 6/18. I had with my boyfriend last Thursday. We used a condom and he pulled out and I'm on birth control so I doubt it's pregnancy. Do you think it's just hormones? Or what else could it be?