I apologize if this is a repeat question, but I couldn't find anything that sounded like the problem i'm having. About a few weeks ago my little guy started this raspy hacking cough. when it started it was only once or trice a day. Almost like he had a hairball..but he doesn't have hair. But now he's doing it a lot more often throuought the day. I do have two other cats that have fur..but he doesn't lick them or anything. should I be worried?