Driver's side headrest deployed for no reason at all. I was backing up in a parking lot when it deployed, and hit me in the back of the head. I have a bump on the head and have had a major headache all day long. Also gave me a stiff neck on the right side of my neck. It was a very loud startling sound. I thought it sounded like a gunshot and thought somebody shot into my car. I had grandchildren with me who thought I hit another car. My twelve-year-old grandson said whoa, Grandma, what did you hit? It was that loud. I have not looked into whether there is a recall on it or not yet, and have not gotten any estimates to fix it. This could have been very dangerous.Had I been driving on an expressway or something because it is very startling when it happens. There definitely needs to be a recall on this.