Does my chinchilla have a cold and what should I do??

My chinchilla sometimes makes whistling sound that i feel comes from his nose not throat. You can't hear it all the time. Then first i could notice one of his nosedrils with a little bit of dry stuff on it and in it. He gets rid of it himself. Today there was a tinny, more white or maybe very light yellow snot. Very small. He paws at his nose sometimes to clean it. He also might have some pain or something with his ear on the same side of his head as we sometimes puts it back. Rearly but i can hear him sneeze. He is eating normally, quite a lot, but was today more sleepy i think. Now he came out of his cage and runs about, he is quite fast, and he seems to be all right. He has just had his dust bath and is exploring everything normaly. Just i can hear that whistling sound more when he is out and excercising.

I have to admit it is difficult to keep certain temperature in my room as heating works as it likes. And sometimes there is a lttle bit of draft that i am always trying to protect him from but i am aware it could be a cause.

Do i have to be concerned? As I see everywhere people say that even a little symptom of some respiratory problem should be taken very seriously and chinchilla should go to a vet. Is it possible that keeping him warm (19-20 celsius), draft free and in quiet place is going to be enough for him and he is going to get back to normal/recover, like humans can?

I will appreciate very much your help.

Plus one more question. He has got a wicker tube hanging under the roof of his cage. He sometimes would go inside and roll. Lately he is doing it quite often like 5 times a day. Is he trying to scratch his ear like that or something that i should worry about or is he just enjoying it?

Thank you for any tips!

Alex