Google 'nasal cycle'. It may be possible to, ah, 'deflate' the turbinate on that side of your nasal cavity by lying on your side with the blocked passageway on the top. Id est, if you can't breathe from the left side, lie down on your right shoulder for up to about 20 minutes.
I haven't had surgery, but I deal with this all the time. If you're paying attention, you should be able to feel the switch in blockage both from pressure and gradual switch in breathing ability.
Of course, it could be something different altogether...