ive had a painful spot at the entrance of my vagina on & off for a few months now. it has gone away at times but i always feel it during vigorous sex. it doesnt burn when i pee, its always the same spot, theres only one spot but recently i have felt it every time I try to have sex & it seems like its not healing. is this a reoccuring laceration from sex or something else? im an otherwise healthy 24 year old with one sexual partner, not on birth control & non smoker.