What Causes Abdominal Cramps And Vomiting?

My 18 year old daughter has had on and off abd pain for the past 7 days...she has had associated vomiting 2x with the pain. She describes the pain as cramping at times with a dull ache almost always. She has been able to do her usual activities until Sunday when she felt ill at work and vomited. the pain today is under her left lower ribs and moves across her abd towards the right hip area...it feels better with pressure on the area for a short time. She rates the pain as a 7 at the worst and a 2 or 3 almost always