Sore sex

Lately I'm so sore around the edges of my vagina during sex, sometimes it hurts so bad it feel like burning, but after we're done, I'm fine... I read that I'm probably not getting enough foreplay (which could be entirely true) but I also read that is a common side effect of endometriosis (which I have)  to have painful, sore sex... Im just wondering if anybody else had this issue and found a topical product or maybe a vitamin, or something that helped? A different method of foreplay?