Every time I tilt my head even slightly up, I feel a sharp (maybe a 4 on a scale of 1-10) and very brief pain in the right upper side of the back of my neck. It feels like someone is stabbing me with a safety pin, and feels like it's happening on the outside of my neck. It doesn't happen when I tilt to the left or right, only when I tilt up. This has been going on for the past 10 minutes, and I had been sitting down for about a half hour when I noticed it. If I move my head around a lot, it goes away, but then if I leave it still for about 30 seconds and then move it again, the pain is back. I know that neck pain is usually not something to ignore, and I haven't had any problem with neck pain before. I've never been in an accident or anything like that. Should I be worried? What could it be?