Alright, so when me and my boyfriend have sex, everything is fine when he's on top or when we're doing any position other than when i'm on top. When i'm on top i get this reallllly sharp pain under my rib cage and it's been worse recently than it ever has been to where i cannot even move anymore and i'm just laying on my stomach crying. i have no idea if something's wrong with me, or what i'm doing wrong. many people have told me to go see a doctor, but i'd like some sort of idea of what it may be and if it's harmful to me before i go to see one. If someone could help me out, that'd be great.