If he's shivering and in pain, he needs to be taken to the vet as soon as possible. Dogs pant when their are wore out or in pain.. and the shivering could be a number of things. If he hasn't stopped by the time you read this, get him to the vet soon!My 45-pound collie/terrier mix, Barret, is on day #3 of a raw diet and now he's acting weird. I thought he was doing better because he stopped throwing up and seemed to be tolerating small feedings. Now he is panting and shivering at the same time. What could be wrong?