If he is scratching his ears alot and chweing at his paws, that is usually an allergy thing also, most often a food allergy.
Paw chewing can be a behaviorial thing, but most often it is an allergy issue, especially since it is paired with his scratching of the ears.
Contact your vet and see if he/she recommends Benadryl. Many vets are ok with that, as another option is steroids like Prednisone, and too much of that can cause liver issues. Not to mention peeing in the house!