Does yawning start a panic attack, or does a panic attack makes me yawn?

Yawning: Either, coincidental at best. I had patients tell me of both.

Panic: Yawning can occur in many people who are anxious. So, it does make sense that someone who is anxious may yawn, and their anxiety may build into a panic attack. See: https://www.medicalnewstoday.com/articles/324401#:~:text=Anxiety%20affects%20the%20heart%2C%20respiratory,are%20not%20feeling%20as%20anxious.