My tiny four pound Maltese/Poodle cross has been coughing and I was wondering if someone has any ideas. He is about 8 1/2 and has had issues with his behavoir. He won't let us have him groomed without him trying to bite us or get his nails trimmed, so every four months or so we have to have him knocked out to have this done. I wasn't sure if this was some of his problem from the stuff they give him or what, but he does it alot especially at night. It's just little coughs, and sometimes he acts like there is something stuck and he gags. It's kind of hard to explain, but I thought if someone had some ideas. If I take him to the vet, they can't examine him without putting him under or he'll bite them. He, also, has issues about if we leave him at home he'll pee on things. He really is a loving dog, and I love him alot, but I'm kind of worried he may have a tumor or something. Please help.