We have a friend whose son was "small" growing up. Short, very skinny. As a teenager they put him on growth hormones to help him out. It's hard to tell whether he got much taller, but he definitely has a more "balanced" physique. Some of that was from the gym, some was probably from the growth hormones. He got into rock climbing where his frame size is an asset for him. He is in college now and looks like he has a healthy build. He will never be 6'3", but that is the way the genetic dice rolled for him. His dad is 5'11' and his mom is average for a woman, so it was just a fluke for him.

Also, most importantly, don't let things that you can't change define you. It's OK to find things to improve on to make yourself happy, but don't spend your life thinking your are "less than" because of your height, frame, or anything else.

Just be good to other people and you will attract the right people.