Sharp Shooting Stomach Pains?

For about and hour now Ive been having these sharp pains in my stomach. Its a kind of pain that I havnt had before. Not like a period pain or stomach upset. It hurts more when I stand up striaght and hardly at all when i sit down and bring my knees to my chest. As I am 14 I am definatly not pregant and my period ended about a week ago. It is a bit hard to pinpoint the exact spot of the pain cos it keeps changing but it is just below my belly on, around the middle of my stomach, but sometimes the pain changes from the right side of my stomach to the left, and then back to the middle again. It is a kind of pain that makes you want to just grab your stomach. But its not a pain that is strong enough to make you scream or make any sounds of any sort. Its just very sharp. I have told my mum and she said to just see how it goes, and see if I still have it tomorrow morning. I dont feel nautious or sick in any way at all. And I dont have a temperature or look pale or anything like that.