Burning sensation 🤔

My boyfriend and I are really sexual. We don't live together but when we see each other, we have sex at least twice on that one day. We don't use condoms and just rely on my birth control pills for protection. Every time he finishes in me, I tend to get like a burning/ stinging feeling down stairs afterwards and sometimes it feels too swollen to have sex again. Feels almost like its sore... does anyone else have this experience? I am planning to speak to my doctor when I see him.