GRYPHONQUEST
I used to have a TERRIBLE time breathing through my nose in Yoga. Turns out, it wasn't anything to do with yoga; my undiagnosed allergies were really THAT BAD. Even with antihistamines flowing through my bloodstream, I still feel like I have to really flare my nostrils to breathe in through my nose; my septum is also kicked about 30% to the right (thanks, swing I fell off face-first when I was three!). I probably look like some sort of demented rabbit sitting there!
So, yeah, same problem, but mine's mostly corrected with nose-flaring and 40mg/loratadine a day!