Cervix Pain during Sex

I've never had this issue before during sex until my current boyfriend and I have been. Every time we have sex and I'm in the rider's seat I have this cramping pain that I really feel in my right ovary and it's sensitive so I have to slow down and work with it before it subsides into pleasure and I have one of those cervical orgasms. I'm not sure if this is normal but he's only the second guy I slept with and I never experienced it with my first. We do plenty of foreplay so I'm well turned on at the point but we've been together for 3 months and it's every single time I'm on top. Any idea if it could be a medical condition or just one of those things that just happens? It's not excruciating and I can bare with it for the moment, but I want to be sure if it's not anything serious. Thanks in advance!