My chest was completely relaxed all the way through the entire lift.
We have figured out why my chest numbers have not been improving, and why I keep hurting my shoulders. All these chest exercises, all these months, I have always been doing just with my shoulders. I'd be told to relax my shoulders, and I was semi-unconsciously think "That's silly, if I completely relax my shoulders, the weight doesn't move". Of course it didn't move, my pecs were too weak to move it, and I didn't have a developed brain/musculature link to try anyway.
So we moved to some press machines, and dialed the weight way way WAY back. Lighter even then it was when I first started training. And I did the reps super slow, focusing and concentrating on pushing and squeezing with my chest, not with my shoulders. We had to do so light, because I've probably never really used my pec muscles for anything, my entire life, they are so weak I didn't even realize they were there, which is probably why I've been using my shoulders in their place all these months.
It's hard. It's like learning to wiggle your ears, or raise a single eyebrow. I was able to get them to "activate" only about half the time, incoherently and inconsistently. Amusingly, I got better at it when they just started burning out, because that gave me some localized sensation feedback.
I was kinda staring to wish for some technological aid. I read a few times about some researchers who studied the mapping of emotional states to facial expressions, and they used needle probes to zap their individual facial muscles, as part of learning how to consciously individually move them. Maybe one of those hokey late-night-advertised TENS based exercise thingees...
On the plus side, this means I have something completely new to work on, and will again be able to enjoy the motivational boost of "beginner gains". And it will really help my build, my posture, my strength, and (hopefully) I'll stop injuring my shoulders.