I get this, among other head noises. Sometimes I'll get what feels like a shock of lightning in my neck and it's so bad, I always involuntarily yell, when it happens. It's like the vertebrae got stuck in place, or caught on the track.
X-rays showed that I have bone spurs in my neck. I did get rear-ended in a car accident once. It snapped my neck back pretty hard. Who knows if it healed right, or not.