Sending prayers and positive thoughts your way. This sounds very similar to a disorder called Syringomyelia common to King Charles Cavaliers and other breeds. It has been seen in Yorkies also. You can check this out on some of their breeder's websites as well as clubs. I read somewhere when we were researching dog breeds that sometimes collars around their necks bother them as it irritates the area. Look for some support groups that are dealing with whatever the specialists decide it is. Research as much as you can, and I suggest you write down any questions you may have. As much as you can arm yourself with knowledge. I know when I have dealt with serious issues with my dogs it helps. At this point I know you are so worried...take care of yourself too.
