@nrd1 My vertigo was caused by misalignment of C1 & C2 that were twisted or tilted and stuck that way because of a muscle spasm prior to my spine surgery for cervical stenosis at C5/C6. When the muscle spasm came on it started a muscle headache in the subopcipitals on the back one one side of my head, or it caused ear pain and jaw pressure. Then if I moved my neck in particular, looking upward so I arched the neck, that set off light headedness and the world looked like it was moving and spinning. I lost my balance and fell down during one of the episodes and there was nothing I could do to stop that from happening. It was like spinning around when I was a kid getting dizzy. If you dart your eyes quickly, it can give that sensation or when you are the first car stopped for a fast moving train that is passing by and you are trying to follow it with your eyes. It really looks like the world is moving and you have to lie down and close your eyes to help feel a little better because your balance is off.

Sometimes just sleeping helps, and that may be because of the resting position that the neck relaxes a bit. A physical therapist can have you lie on your back to put the muscles on slack, and feel the spineous processes that stick out to the sides to feel if they are aligned. If you put your thumbs behind your ears, and feel for the notch at the base of the skull, that is where the spine processes of C1 sit just below that. My PT showed me how to check this. You should see a PT about this rather than try to fix it yourself because if there is spinal instability, that can have a lot of risk of serous injury. The vertebrae can be realigned by stabilizing the shoulder blade on one side and turning the head away from that against resistance from your hand pushing against your head, but you need to know what your pattern is for muscle spasms. That gets your muscles to realign the vertebrae by contracting and moving them. My spasms started on the left likely because my neck is tighter on that side because I have thoracic outlet syndrome that is worse on that side. A physical therapist is the best person to help figure this out and to work on correcting it. The vertebral artery passes through the side of the vertebrae, and having them twist and stay like that will stretch it, and can alter blood supply to the brain. That is what happens with Bow Hunter's syndrome which is much more involved than what I experienced. Since my surgery, my neck has calmed down and vertigo doesn't happen anymore after a C5/C6 fusion. I can still cause a muscle spam if I strain my neck position,and get a slight headache on the back of my head, but I can massage my neck and get it to stop.

Here is a link with some information.
https://americanmigrainefoundation.org/resource-library/vestibular-migraine/