well my girlfriend for about the past week and a half has been experiencing stomach pain (not really nausea) every night for at least 4 hours. it only occurs during the night hours and has subsided during the day. It usually comes on around 9pm and lasts till 2am or to where she falls asleep and doesn't notice. But like I said she works during the day and it doesn't bother her but at night is when it kicks in and some of the pains seem to really hurt her to the point to where she has to lay down and stretch her stomach. Does anyone have any answers?

EDIT: SHE IS ON BIRTH CONTROL