It does not sound like you need any diagnostics other than the gifted hands of somebody to keep your neck in good health. A generic chiro does not impress me at all. Same goes for Physio. One needs tyo keep looking until one finds someone who understands and makes a difference.

The one thing you do need is help with anxiety.

We have seen many who ride a long roller coaster until they get help with their anxiety. If you were anxious before PCS, you will be many times more anxious with PCS. So, I suggest you focus on your anxiety as a priority.

What are you doing to help your neck heal ?