Asthma - Normal Symptoms?

I have had asthma for about 20 years and have been on Advair for a few months. Over the past year I have noticed if I talk for more than 5-10 minutes, my lungs begin to feel irritated, feeling like I have a chest cold. I also have to clear my lungs frequently of small amounts of mucous. My lungs and voice sound and fell like they're dried out. Oddly, I don't seem to have any trouble breathing. My chest doesn't feel tight and my peak flows are in my normal range. Over this same period of time, I have mild lung discomfort almost all the time, like I have a chronic chest cold. But I don't cough nor do I have a fever. Are these symptoms consistent with asthma? Are my lungs being damaged by this and does this mean I'll have serious lung problems as I get older?
Thanks