Max has been getting fish oil for years. He also takes glucosamine. Our latest vet visit showed nothing new, xray-ed his throat and ear canals and the doctor insist that he may just have old man syndrome. The only other option is to go to a neurologist and have a nerve scan done. We will just let it go for now but will continue to monitor him for any changes.
I have a 10 year old Chessie that is doing what your dog is doing . He also had pancrantitis at 2 and the vet is stumped. He groans going down and while lying down, otherwise he is spry, happy and active. I will follow your post to see if you find out anything. No he is not dreaming.