I've had this pain it's sort of on my back and side, it's come and go twice now, I guess it feels like a cramping pain but on my waist. When I apply pressure it fades but it comes back, it sort of throbs. It's really discomforting, should I see a doctor?
Robin, is the pain on your right side, by any chance?
If so, get your stepmom to take you to the doctor and have an ultrasound done to check for gallstones. It's in the family, and even your sister has them so it's a good possibility.
Does the pain go from back to front? If so its probably a kidney infection, drink lots of water and cut the sugary drinks for the next few days, if it doesn't get better I suggest seein a doc