Puffy Vagina

So in my previous relationship whether or not I had sex or masturbated, my vagina would get puffy and start burning. It only happened about 4-5 times and it would inflame so much it would be able to be seen through clothing and be extremely sensitive to touch anything. I can rule out condoms and latex Allergy because it happened while I masturbated as well So I'm not sure of what happened to me help if you can it will be appreciated!!!! And also no STI's or STD's because I've been checked and we were each other's firsts.