How To Treat Muscle Pull At Back Due To A Accident?

when I was 15 yrs old I was in a car accident and I had bad whiplash. We were hit from the passenger side. Ever since then I've had problems with my right shoulder. But back in february I woke up one morning with a crook in my neck. As the day went on the pain got worse until I couldn't move my neck. And I began to get this shooting pain down my back. And for about two weeks or so the pain persisted and then stop and started again. I finally went to the doctor in march and she said that I pulled a muscle in my back. Now it july and I'm still having the same problem. She prescribed motrin and flexiril for pain but the muscle relaxant didn't help and the motrin helped with stiffness.