genetics
you are an ectomorph
good arms narrow torso
this.
only so much you can do with genetics like that.
all your injections from now on should be in your delts. give them an artificial fullness.
standing side db raises, reverse pec dec machine, cable shoulder press. (i feel this in delts more then db presses), standing front raises.
use a weight you can control and go to 10-12 clean reps. heavy weight your swinging around is not what you want.