A little clarification to my comments above about the herniation from our chiari malformations moving up and down with each heart beat. The specific reason we frequently feel throbbing in sync with our heart beat is because the cerebral spinal fluid (CSF) moves with each beat of our heart. So, particularly when a patient has diminished or blocked CSF flow, we feel that throbbing in sync with our heart beat, because with each heart beat your CSF is trying to cycle from the spinal canal, up to the brain, and back down again. That is what you see reflected by the CINE MRI in the brief YouTube video I shared in my last comment.
Also, sorry to have missed your recent posts until now. I was gone for the weekend, and pretty much offline the entire time.
Today I woke up after a very good night's rest feeling substantially better, but for the prior three days I woke up with terrible neck pain and the typical sensation of pressure at the base of my skull. Your symptoms sound very similar to mine.
The throbbing sensation is also to be expected. Our herniations (especially when they are under extra pressure from blocked or diminished CSF flow) do move in almost piston fashion with each beat of the heart. Take a look at this very brief YouTube video showing the sort of 'piston' movement of the herniated tonsils. You can literally see the herniation moving up and down with each heart beat.
https://www.youtube.com/watch?v=WSwjMtn3Txo
My posture when sitting is one of my biggest problems, so getting up and walking helps me tremendously. For others, laying down helps them the most. Whatever works for you, I recommend getting into that position, or doing that activity to assist your CSF flow as much as you can until the episode passes.
I sometimes combine my walks or times I'm resting by laying down with breathing exercises. The breathing alone isn't going to change the herniation of my tonsils, but when I do it right it does bring my heart rate WAY down. And, in light of what we see in the linked YouTube video, where the herniation is moving up and down with each heart beat, you can imagine how this would be helpful in the long run for avoiding further herniation, and in the short term for easing the blockage of CSF flow, allowing the backed up pressure in our heads to slowly get past the herniation.