I've never been able to breathe through both of my nostrils. One of them is always blocked/clogged. I've been reading about deviated septums, but it seems like that would just affect one side or the other and it would be constant. Mine alternates all the time - sometimes I can breathe from the right, sometimes the left. I've been waking myself up at night because I can't breath well. I have an appointment with my doctor in a few weeks to discuss.
It probably is a deviated suptum. I had my nose broke about 15 years ago and never had it fixed. I was told I have a deviated septum and I have the same symptoms as you. It never really bothers me except sometimes when I want to try to smell something and breath in. I don't hardly notice it except when one side switches over to the next it's kind of weird. But you can live with it I would say?
I agree with you guys.... sounds like a deviated septum. I've been having the same problems for years. I've always got some nasal blockage - either one side or the other... or both. I'm having a septoplasty (to straighten the septum) as well as a tonsillectomy on Friday.