How long ago was your mva? You could have a bruised spine (traumatic myelopathy). In that case, you could have your symptoms, but without structural damage that would show on an MRI.

If your spine is bruised, swelling could be interfering with nerve signals. When I was first injured, I had a neck circumference that would have made a linebacker blush.

As the swelling reduces, your nerve may come back online. Nerves can regrow, but very slowly. However, having been down for awhile, it could take time for them to send the proper signals. It can be quite painful, when the nerves "wake up." Other nerves might just be dead or permanently damaged.

Overtime, I got somethings back, but not all. For example, I have very little dexterity in my hands. In my case, I had both bruising and structural damage.