[XXX]: Driving down a city street, had not braked or slowed down when I heard a loud bang behind me and something hit me in the back of the head. My son was in the car with me and said the headrest had exploded. I had nausea and a headache for a couple of days, which indicates a slight concussion. Saw my doctor the next day and he said to let him know if it got worse, which it didn't. Took the car to my dealership where I purchased the car, Bill Luke Dodge, Phoenix, AZ and they said the headrests were added to my cars warranty, but since my warranty had expired a little over a year ago it wasn't able to be replaced free of charge. I also need to get the passenger headrest replaced before it injures a passenger. It's almost $800 to replace each headrest. I had multiple items fixed under my warranty just before it expired and feel the headrests should have been replaced also. I would have requested they be replaced if I had been notified there was a problem with them. I was driving down a mountain with sharp curves approximately 2 hours before this occurred. If I had still been in the mountains there's no doubt I would have had an accident. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)