If you are not building muslce, one of two things are off. 1) Your knowledge of how muscle growth works; in which case you will need to educate yourself. or 2) You are not training as hard as you think you are. Really think to yourself, why you cannot put on muscle. There are 3 keys to gaining muscle: DIET, EXCERCISE properly, and Rest. If any of those 3 are off, you will not gain that much if any.