I do have this, and girl does it hurt bad sometimes.Lightning crotch will hit you out of the blue and sometimes it will literally make you flinch hard. Sometimes the pain is really quick and it's gone, other times it goes off and on for a few hours. I get it at least once a week. It is the uterus growing and putting pressure on the cervix, and/or it the the baby kicking your cervix. I've read it's perfectly normal and some women get it more than others. If it hurts bad and doesn't let up I would call your doctor and just ask to make sure to be fully safe.