I wouldnt say i am totally pain free in my shoulders, but i can say i have noticed less pain. I am not a Dr., and am not pretending to be able to explain why, but i am guessing that it has to do with increasing the strength in the back and aiding in the correction of posture that detiorates from a lot of pressing with an unequal amount of pulling.
I think of it like this:
chest < back = shoulder pain
chest = back = no shoulder pain
Love the Kroc Rows. Love the pull ups. So do my shoulder guts.