Shoulder is a big factor Bro.
Sounds like you've got it figured out as far as what to do.
Only thing I could add is to do more warm ups for the shoulder.

Form is always something to consider - good job on identifying this for yourself!

If you want to try to get a little more out of the chest - when you're done with your workout - go to the cables, put handles on the bottom of each side, set it to a comfortable weight and do a few crossovers by crossing your arms in front of you all the way across your chest alternating left arm in toward the chest on one set and then right arm in toward chest on the second set.
2 sets of 10 - 12 if you can.

If there is any pain - stop and don't try these.
But if you feel a little pump when you're done - bingo!