The nerves in the neck travel down the arm to the hands. Your arm and thumb hurting are probably pain traveling from your neck. It could be from being jared so severely or it could be you have damaged a disc or two in your neck which is the Cervical spine. If a disc is ruptured it can be pressing on a nerve and cause pain all the way to your thumb. I would strongly recommend that you have an MRI done of your neck to make sure your disc's are OK. Xrays do not show damage to disc's. I am not sure what you are taking for meds but they do have some strong stuff out there to help more. I had ruptured a disc in my lower back and could not walk the pain was so bad. They gave me Flexeril and Toradol which honestly didn't help a lot with the pain but within 10 minutes of taking them I was out like a light even if I had already slept for 10 hours. Vocodin is also good for pain but it depends on the kind of pain. It didn't help my nerve pain but it got rid of the back surgery pain. So you'll probably have to try a couple different pain meds to see which one works for you. All in all when I was at my worst believe it or not Advil liquid gels seemed to really work the best. Not the tablets make sure it's liquid gels. I hope some of this helps. Also you should put ice on your neck for 20 minutes about every hour if you can or every few hours. When you are first injured you need ice to bring down the swelling. That's what my doctor told me. No heat you need ice packs at this point.