I am a pretty small guy. 5'9 about 160. Probably 12-13% bodyfat. Despite being pretty small all over, a bodypart I notice lagging a lot is the deltoids (among others, but I'll deal with those later). I have problems with my shoulders pretty often when I work out. I hurt my rotator cuff a while back and my shoulder has never been the same. Although both shoulders have problems when working out. I was wondering what the best exercises would be for putting some mass on my delts. Maybe someone has some advice for what has worked for them?