What Causes Pressure And Pain Near The G-spot Area And Abdomen After Intercourse, Especially Since Using Plan B Two Months Ago?

About a month now my girlfriend feels like there is pressure and pain during intercourse in the area of her G spot. Sometimes it’s fine, and sometimes rather painful. Over the last month she has pressure and pain in her abdomen in that area for a few days after intercourse. Nothing else is unusual and everything else is operating as it should. Her abdomen is swelling slightly and it all seems to be generalized around this area. About 2 months ago she used a Plan B, and has since had normal periods and again nothing else is out of the ordinary. Sometimes I can feel I’ve hit something during intercourse as well.