I'd try the doorway pec stretch (arm up at 90 degree angle). If you are like 99.999% of us lifters, chest is super tight (esp pec minor). Stretching it can help to improve your shoulder health and posture, and allow your scapulae (shoulder blades) to retract and depress more as they are designed. Basically, stretching the antagonist (oppossing muscle) can help allow the protagonist (rhomboids, etc) to relax more.
Terrible analogy b/c I'm tired - Tug of war - you (rhomboids) are on one side, and the cast of Biggest Loser (chest, anterior delts, lats, etc) are all on the other side. You are going to be pushed to the max to hang on to the rope b/c of the opposing force, but if you can wave a cheeseburger in the air and get a few of those fatties to drop the rope (releasing the tight mucles in front, ESP pec minor), you'll have to work less. FYI - when I do that stretch, I find it takes some playing w/ my body lean, elbow height up the door frame, and how far I step in to the doorway, in order to FEEL THE STRETCH through the pecs.
You can also foam roll your pecs, and I find this one is actually a bit painful in relation to other body parts, but it's all relative.