Hi and welcome to the Chiari forum.
First your CM is not 5 mm's your herniation is.....Chiari is the malformation of the skull....causing it to be too small to hold the cerebral tonsils....which herniate as a result....when the tonsils are forced out they can block CSF flow, compress the spinal cord and brain stem.....
Chiari also comes with other related and non related conditions so many of these conditions cause symptoms similar to Chiari.....
So you had a CINE MRI done? And a brain MRI and a cervical spine MRI....a thoracic and lumbar MRI?
It is ALL in your head, but not the way many Drs may insinuate.......