Ovarian cyst?

So sometimes when my partner & I have sex I feel a sharp pain to where I have to stop! It usually happens closer to when AF is on her way. But I also heard hotter story's that it could be a cyst/: my mother had ovarian cancer! (Healed thank god) so I'm afraid I could get it:(.. Could it be a sign of ovulation. Or a cyst. It's so painful.