Im 16 years old and ive been having these really bad stomach pains like im being stabbed in the stomach im not pregnant i know for sure but its like in multiple places in my stomach and it hurts really bad its like to the right close to the bottom of my rib and to the left same and near the center and also like toward the upper stomach area near the top of my ribs and multiple places in my stomach area its like being punched several times then stabbed and sometimes it hurts so bad i cry it will hurt all day then stop near the end of the night and then ill wake up and be just fine and then about every once a week it happens. Whats wrong with me?