May be tmi for some but my fiancé and I have a active sex life, and he's been aware of my growing belly (I'm 23 weeks) and we both like it when I'm on top, but lately I've been having this pain, I can't get going like normal or I feel like I have a pulled muscle near the uterus, it was just the left side, but last night it was the right side, and its only during sex?