Why is my dog pacing, restless, and can't settle? Home remedies?

Hi and thanks for using Petco Pet Education Center, formerly Petcoach! Sorry to hear about Bo. Three things in particular that I would be concerned about- back or abdominal pain and anal gland problems. A common back problem that we see frequently involves the intervertebral discs which are between the vertebrae. This can range from the disc bulging against the spinal cord or a rupture of the disc. Dogs often pace, move cautiously and slowly, seem painful, can't get comfortable for any amount of time, etc. Back problems can also be due to soft tissue problems such as a muscle strain, other inflammation, infection, etc. Abdominal pain can mimic this same presentation even with a lack of clinical signs. This could be due to intestinal cramping, pancreatitis, kidney pain, or problems with any of the organs in the abdomen. I'm mostly suspicious of a back problem. I would advise keeping a very close eye on Bo. If this condition persists, worsens, or other signs develop then I would have him evaluated immediately. If you notice that he is getting weaker, seems uncoordinated, starts walking on the top of his back paws, becomes paralyzed in the rear legs then get him seen immediately. These signs would mean that he is having some significant pressure on his spinal cord. Anal gland problems range from enlargement to inflammation to infection of the glands. Clinical signs are often vague like this.
Your vet can gather a history, perform an examination, and then make a diagnostic/treatment plan based on their findings. Possible tests include fecal/blood/urine tests and x-rays to evaluate the spine and abdomen. Anal glands can be emptied if they are found to be enlarged and painful. Treatment would be targeted once a diagnosis is made. Good luck with Bo