Suggest Treatment For Dry Cough And Shortness Of Breath

Over 4wks ago, I went to Texas and although I love humidity,it started to make me feel "stuffy" in the nose. It may have been from the airplane however,I did not feel that way until about the 2nd day there. The only allergy that I had was penicillin,amoxicillin and severe weather change has never had any negative affect on me at all. I am a healthy active 35 yr old girl. In the first few wks I was only congested & had a slight tickle in my throat which I took nyquil & cold eeze for. Then I started getting a hearty cough but it was & still is dry with no mucus at all. Also I have not bbe sick in 5 yes and I would knock out any sign of a cold quick. I also usually take "airborne" and keep antibacterial wipes with me at all times.this past week, I've had a worse cough at work possibly due to the air cond. And past week have had a weird feeling in my chest with slight shortness of breath. I work for a foot dr. But asked that he do an xray which did not look super cloudy at all but he says it showed slight white cloudiness & he was not sure what to prescribe,but ended up prescribing "avelox" which I am hesitant to take since he didn't even sound sure. Help! Thank you.