What Causes Vaginal Area Pain During Intercourse?

my girlfriend and i have been having sex for a while now, nothing too crazy no anal or anything like that her problem is this though when we are having sex she will all of the sudden have pain on/in her vagina area to the point that we have to stop suddenly and the pain will stay with her for 3 to 4 days after so much so that i can't even touch her and all she wants to do is ice it