Damn man hope you heal up fast. broken ribs are no fun, been there done that. the rest of it sounds... worse.
I think we can all agree on the head part ! (Buddy !) A couple of years ago, a guy I know borrowed my “B” bike, and managed to go pretty well ...
I was leaning in this direction, with slop being created in the shift rods wreaking havoc on the behavior of the quickshifter (which I assume is in place here). SBU put a video on their Instagram stories about a week back from a customer who had a pretty extreme case, but I think they were steel bearing inserts that were very worn.
I used them on my bike and ran into shifting issues that took me a little to figure out. https://www.mcmaster.com/8411k111 As the rod ends were heating up due engine heat they were expanding and causing the linkage to bind. I was getting missed shifts towards the end of a track session but not at the beginning. Seems obvious now in retrospect but I was scratching my head as to what the problem was. Put the stock rod ends back on and the problem went away.
Was it painful when they poked through your chest to re-inflate your lung? I remember that hurting me more than the accident when I broke my ribs and collarbone.
i had (2) chest tubes this year during the same hospital stint (non moto related) and the tubes were by far this worse part.
It could possibly not be the rearset's fault. The position of your foot on the peg could be the culprit. The left hand turn is where this phenomenon is most likely. Your boot can press on the shift linkage (not the lever) and be causing the shift that you are assuming is a popping out of gear situation. I think Vortex sets are more apt to this scenario. I had similar trouble and figured it out at the track by moving my left foot slightly when wedging the boot on the peg for the left hand corner. When you get healed up you may want to play with foot position. Just a suggestion based on my experience. Feel better soon.
I did that one time on a straight. Full throttle and my toe out just enough pressure on the lever to engage the ignition cut. It scared the shit out of me and about threw me over the front of the bike.