What Causes Severe Back, Neck And Shoulder Pain?

I am 21 years old I have never had back pain prior to this accident, I am 5'2'' and 160 lbs. I was in a car accident three months ago. My whole body was sore for about a week afterward followed by aching in my mid back, then two days ago i went to lay down and all the sudden felt severe paint in my neck upper back and even shoulders...i can't reach outward and i cant turn my head left or right. Could this be from the accident and how severe could this be?