I have not jolted my neck or had any trauma. If I had to guess, it's from sleeping on a CRAP mattress for just over a year. Till we got our new one about three months ago, I was waking up more n more feeling like I had been punched by Mike Tyson in the mid to lower back. My Chiro has often told me that messed up necks are because of LOWER back issues. I also wish I could relax more during adjustments. I HATE HATE the feel of my neck being snapped! LOL Maybe I should do a Chiro trip while hammered!