Re: Nasal congestion on one side?
If it is fluctuating from side to side, this is just the normal nasal cycle. The congestion changes side every 6 hours.
"Your two nostrils shift their workload back and forth in a delicate dance called the nasal cycle. At any moment, most of the air you inhale travels through just one nostril, while a much smaller amount seeps in through the other. At some point, the nasal cycle reverses course and the workload shifts to the other nostril. The length of time between nostril switching varies, depending on the individual and various other factors, but each cycle usually lasts from 40 minutes to several hours. (Thatís why you often have intermittent periods of easy breathing even when you suffer from a heavy cold. In this case, one nostril is plugged more than the other.)"
True congestion /sinusitis usually does not let up, regardless of what position you are in, although it will be worse when lying down.
You can always see a Dr. and they can tell you if you have a nasal obstruction. The first line of defense would be to try corticosteroid nasal sprays( Flonase, Nasonex) to see if that helps.