Hey man, i had the same problem in high school, no matter how much good food i ate i wouldnt grow until i started packing 5000 calories into me, and those calories didnt include the 1k calories from protein. I started pounding in wendys burger king mcdonalds, ICE CREAM SHAKES, i would drink olive oil. It sucks for us hard gainers man, but we have a gift (we cut EASY!)

Lift heavy, eat like a horse, and i promise you will gain size.

The metabolism will slow down after high school. I guarantee it lol.