In 2002 I was hit by a drunk driver and it did a number on my neck, back, shoulder area. The pain comes and goes from time to time. If I had to give you one piece of advice to get you through some spasms it would be to;
1. Have X-Rays done to make sure no structural damage has taken place
2. MRI if you can to make sure there are no disc herniations
3. Lay in a warm bath tub for 30 minutes daily.
Little things can become big things over time if nothing is done about it. I hope you feel better and I kow what it feels like.