I'm wearing the same pants as John Meadows right now. For a second, I was like how did they get me on camera?
If you're mid/upper back (rhomboids, lower traps, extenal rotators, whatever they are) are really messed up, you can hit them 2-3 times every day at home with stuff like scap pushups, band pull aparts, band or broomstick dislocates. Even stretching your pecs will help.
On upper body days at the gym, warm up with Scarecrows, or Y/T/L's, or prone trap raises, or bat wings, or seated dumbbell cleans, or face pulls. All these moves kinda do the same thing. Pick one or 2 that you can really "feel" and do a few sets to get going, before your real lifts. This should help you get set up for bench pressing. And improve your stroke on overhead pressing.
Whenever you do rows, remember Meadows squeezing his shoulder blades together. Do that. Then focus on getting your elbows behind your back. Don't worry about rowing the handle/implement to your chest. Think about getting the elbows back and puffing your chest forward, using the mid-back muscles.
I've been using a chest supported, seated iso-row machine. I remove the seat, and row standing up. Then I try to recreate my bench press arch, rowing and arching my chest into the pad. I got this from Eric Spoto. I was able to start really light and get the "feel" I was after.