pbojan

Hi, to all I’m new here few years ago I bought my AG from a guy that was moving, he already had it for 2-3 years and now he is around 5 years I don’t know exactly. Last winter he had the same problem like now he is breathing heavy, sounds like nares congestion. My vet gave me Enrocin 10% drops but it didn’t help. Can anybody tell me what to do? Is this a big problem? Could it be from the dry air in our apartment at winter time? Thank you