My shitzu has a paw problem. We have taken him to a vet and they have looked and can find nothing amiss. He won't let me touch one paw, any ideas out there?

did they x-ray? did they check the shoulder? I take it they muzzled him or tranq'ed him to examine it?

they really need to shave all the hair out from between each pad - it could be a very small thorn

[wishbone]

His paw maybe painful or have an infection.

Or it could be an injury or a piece of small sharp thing hurting him, let a vet or two examine your dog's paw to make sure.