I think you might want to bump up your rep range. I dont get a great pump in the chest or soreness unless I include either a 15 rep set with slow negatives or atleast a drop set. Dumbells feel a lot better than the barbell as well. If you are doing 4 sets I would suggest 2 at the range that you are already doing then on the last do a drop set, slow negatives that will let you get about the 12 to 15 range. Then finish with some Dumb flyes.That should force some blood in there. Just my 2 cents but I hope it helps.