Ears and rears? What is that? My dog is constantly rubbing her ears but she doesn't have mites, and sometimes she's so uncomfortable with what appears to be an itchy butt (she keeps licking it, and wandering and laying down, like she's trying to get away from her own butt). Sorry to be so graphic...

Ears can be bothered by many other things, matter of fact, ear mites are not typically a dog problem.
It could be a yeast or bacterial infection, it could be allergies or fleas.
Lift the ear and look inside, this sounds gross, but smell them (yes, the inside) many times with an infection there will be an odor that goes along with it.
The rear end could be anal glands, fleas or again, allergies.
Only a vet who can examine him can tell for certain.