Mmppaa

What is the name of your state? NC
I was involved in a rear end collison in April 2003. Stopped in traffic and another car ran into the back of my car causing me to hit another car and that car hit yet annther car. I suffered injury to the right side, head, neck and shoulder. I had a headache that lasted 3 months. I do not have a lawyer because I do not plan to sue the young man that hit me. Now his insurance company is trying to settle and have offered me, what I feel is a very unfair settlement. My medical bills are $8,000, plus time from work and travel for therapy treatments. They have offered me $500.00 for diminished value for my car. I, thank God, have never been in an accident before and hate the words whiplash and law suits. I want to be reasonable, but I an not willing to take a loss on this accident. My car had over $7,000 in damages. I still have limited range of motion turning my head to the right. How should I calculate my settlement? I want to be fair but fear I will always have trouble with my neck and right shoulder. How do I calculate a reasonable settlement?