What kind of lifting program are you working on and how often are you lifting?
I've been dabbling in lifting for a few years, but haven't been able to put on much muscle due to all the other extracurricular stuff going on in my life. I do Brazilian Jiu-Jitsu 3/4 times and play soccer once a week . . . so really only have time/strength to do lifting two days most weeks.
I'm currently doing a 5x5 routine of either: Squats, Bench, Rows or Cleans, Military Press, Deadlifts