That's a lot of weight to push.
My right shoulder (separated when I was 19) gets cranky with anything heavier than 275 for reps (or it did last time I tried).
Yeah, I rarely do BB stuff for chest since it bothers my right shoulder. Dumbbells don't bother it that much, though I should probably use those for incline work too instead of the machine I'm using. BB incline doesn't ever bother my shoulders, but I feel like I get so much more out of DB work.
I can definitely feel my shoulder get annoyed when I'm doing pullups too, which is weird. I've been slacking with the prehab stuff though, I think this is a lesson to get my ass in gear and start doing that 2x a week.