While I was driving, I was hit in the back of the head causing me to get dizzy. I thought someone was in my van and punched me. I slammed on my brakes and jumped out. No one was in there. It was my headrest that deployed. I didnât know that a headrest deploying was a thing. I noticed a small plastic piece on my seat. After looking at the headrest, itâs visibly broke. I have a migraine headache, left side neck pain, and have to drive with my seat back further as to not have my head tilted forward when driving. Had I been going faster this could have no doubt caused an accident.