I slept in that splint thing you recommended last night @BethB - that’s two nights (well, a night + a couple hours) in that. I can straighten my arm a little more today, so I’ll say it’s helping.
This morning I got in a pretty decent push workout where I was able to do some machine pressing starting the movement just about 90°. My right pec isn’t flexing exactly the same way, which I figure is just due to the discomfort on that side.