lol....you answered your own questions. First off, there's NO shortcut to get strong. However, there is a silver lining to your ectomorph body. Tall and skinny, + a lot of training and FOOD = tall and muscular. You won't need to worry about getting fat. My condition was similar to yours, till i decided to go for martial arts.

Only way to get strong, is to train. You can either train yourself, or have somebody train you. The latter is good if you don't know how to start. You can either pop by the gym, or find a martial art/dance instructor, or find some friends for sports. You'll need self motivation for the gym, be able to tolerate a lot of PAIN for martial arts, and a good group of friends for sports. Either one will help build you up as long as you do it frequently enough. 2 or 3 times a week of intensive action works for me.

BTW, i also have asthma. Was hospitalized 6 times as a kid. It's not a real barrier to getting fit. Just takes you a little longer.