Any instability in this area could be causing a ‘pincer’ action on the underlying brainstem/spinal cord, see the 2 dots.
This could cause turbulence in the flow of cerebro spinal fluid, as well as irritate the underlying brainstem/spinal cord.
Whilst you’re waiting for further appraisal, my advice would be to wear a Philadelphia collar (with linings!) 24/7. Persevere with it (because it is cumbersome) but notice the improvement, some might be immediate and other symptoms will subside over time.
Click thumbnail to see full-size image