I have suffered with this in the past - but a physio at work helped me no end.When she manipulated my neck it felt like she was thinking about strangling me (and who knows what she was thinking) but within a minute of her working on my neck, the pain started to resolve.
Her suggested self help remedy was to get a bath towel and hold it so the leading edge is against your lower neck, then pull the towel tight in a gradual forwards and upwards motion. Repeat this at slightly higher levels on your neck sequentially. If you look at a diagram of a human spine, you will see that the neck vertebrae have long tails and with advancing age these can tend to lock against each, and it is this that often causes the spast type neck pain. The towel helps exert pressure to realign the vertebrae in an inwards and upwards direction that helps to separate any that are rubbing.