I’m A Young Female Under The Age Of 21 And

I’m a young female under the age of 21 and quite thin and when i push on my stomach it feels like there’s a large hand size lump in my somach kind of under my rib cage and ends at my belly button. It’s not usually noticible when looking at it only when i suck my stomach in. I’ve had a weird stomach pain a couple times. It’d just weird cause it feels like a have a big rock in my stomach cause when i press on it it’s kind of firm.