Random question but just wondering, when most boys go through puberty do the majority of them get taller and lean? Most boys in my school have including me, wondering if it's for every boy.

It sounds like they've gone through a growth spurt, making them taller. Their weight hasn't caught up yet with the growth. Some will grow by several inches at one time making it more noticeable. My son only made it to 5'8, so when he grew, it was an inch at a time - not so noticeable. Most guys continue to grow until their mid-twenties.