Vagus nerve
I don't know about choking, but I know that yawning really large can pinch your vagus nerve and cause you to faint. I know this because it happened to my son when he was in college. He was sitting in class during a dreary afternoon when rain was moving in, and he couldn't stop yawning. He finally let loose with a really large yawn and suddenly slumped back in his chair, went into a short episode of jerky spasms, and then fell unconscious. The college email was called and they transported him to the hospital and called me to meet them there. It turns out that when the vagus nerve is pinched like that, it's similar to pushing a reset on a computer system. The nerve "shuts you down for a few moments" before your brain boots you back up again. Totally normal response. So, I could see where if this nerve was damaged in some way, it could cause some real problems down the road.