Acute muscular wry neck I imagine. Quite common, Scottie, and it will settle down fairly quickly. Just don't irritate it too much or it will react by spasming.
Let the hot water run on it under the shower and try to move within pain limts. Massage, physio and acupuncture can help a lot, and even diazepam (valium) - muscle relaxants. After the acute phase is over, hot packs (like wheat bags) can help, too. Sometimes there can be a little bit of disc irritation involved, but if your pain is only isolated to the neck you should be fine. Cervical discs refer pain to the shoulder blade region, particularly when flexing the neck.
Just be patient with it. If it's been going on more than 10-14 days, get it looked at.
BD
Winners make it happen...losers let it happen.
Qui audet adipiscitur.