If I swing my head from side to side (think shaking "No" very quickly, there is a distinct crack/pop sound. If I leave it for more than an hour the noise is audible, but less than than it's only ...

Neck crepitus refers to clicking, cracking, popping, and crunching sounds in your neck when moving your head. Popping at the base of your skull can be surprising, even alarming, but common issues like ...