My Dog Is Cold And Shivering. Shivering depends on so many things. Your dog may be shivering and lethargic because he does not feel well.
Excessive shaking is another way your dog shows signs that it may. You can easily help by turning up the heat, snuggling up to your pup, or helping your little friend into a cozy sweater. Or, it could be a sign of any common problems such as stomach or diarrhea.