Breathing difficulty

I have been suffering from ethmoid sinusitis, for which I have been taking alternative medication. I also suffer from blocked nose, and take "otrivin-o". Since two days, i have been finding some difficulty in breathing once in a while. I am able to breathe normally, but once in a while i have to make an effort to breathe/take in air. I also have some throat irritation, cough but no pain as of now in the throat. Why is there an occasional difficulty in breathing.