I have adult onset asthma that has gotten progressively worse sin...

I have adult onset asthma that has gotten progressively worse since I moved from a small Midwestern town to a larger city in the Sonoran desert. On account of this progression in asthmatic symptoms and flair-ups, I switched from Flovent 220mcg to Advair 500/50 about a year ago. For a long time, Advair really seemed to be helping my asthma. Outside of gaining 10-15 pounds in this year (which I asked my pulmonologist about and was assured that inhaled steroids cannot be responsible for), I have fortunately not had many of the aforementioned side effects. However, in the past month after experiencing a bad flair up while studying abroad, I have developed severe heartburn, nausea, acid reflux, a sore throat, and mouth sores. I take the medicine as prescribed and am always sure to properly rinse out my mouth, having been warned about this. After reading everyone else's entries on this site, I am now curious if Advair is doing more harm that good.