Last night I got out of bed to get a drink of water. When I came back I walked in my bedroom and started laying down on my bed. Right in the middle of laying down I got this sharp pain above my left rib cage, and about 2 inches below my left nipple. I immediately stopped and didn't move. The pain was only in that small area (not across my chest or anything). It kinda felt like I had just gotten punched there. It seemed like it worsened the more I would move, so I very slowly got out of bed and walked around. Then it disappeared, I've never had anything like that in my life.

I'm a pretty healthy 19 year old male. I could stand to lose maybe 25 or 30 pounds, but that's the only bad thing about my health. I had a blood test done a few months ago and everything came back 100% normal, and they said my blood pressure was excellent. I don't drink alcohol, and I've never smoked anything in my life.

What on earth would cause something like this?
(Sorry if this is in the wrong forum, wasn't sure where to put it.)