One of our cats, Frankie, will be sleeping or just laying around and he will start hacking like he has a fur ball but nothing comes up. He does it in the middle of the night, you name it. He almost sounds like he's wheezing when he's doing this. You can see him straining to puck but nothing comes up. It's been happening a lot more the last few days. My husband said he was sneezing today too. Can it be a cold? Or something more serious? I'm not sure what to do.