Pain! SEX

I want to know if anyone had this or has this happening. I've been sexually active with my boyfriend for  almost four years. In these four years I've had random cramping up during sex. Not always either. It is random. I have to have him stop because I feel like my ovaries are being stabbed. I've went to the doctor before and had an ultrasound and they told me I've had a ruptured cyst. However, the other night I had this pain again but 10x worse, I was crying so much and had to take an extremely hot bath for the pain to calm down. Help!! Anyone know what this may be?