Dumbbell FTW. I like to turn in the wrist in for the extra squeeze. I dislocated my shoulder 6x in Ice Hockey, this made my right shoulder more dependent than the other. Thus using barbell made my left chest slightly bigger ( not noticeable unless you stare at me with out a shirt). Since then dumbbell is what I throw around at the gym, even on shoulder and some rows as well. Good Luck and don't ignore the pain.