My 15 year old daughter started having sharp pains in her upper abdomen (just below her sternum) in the middle of the night. The pain is not so severe as to keep her from functioning, she just mentions the pain. The pain seems to subside if she hunches over, but hurts if she sits up, or stands up straight, or takes a deep breath. She hasn't lost her appetite, no fever, no vomiting, no diarrhea, no constipation...she doesn't have any other symptoms besides the pain. Any thoughts?