Hyperextended lung and viral bronchitis

I have a quick question.  I went to see my family practioner today, since my lungs have been burning, my chest feeling heavy as if someone were sitting on it, and I have a steady cough, no congestion.  But when I cough, my lungs are so tight with this burning sensation that it is hard to quit coughing.  Anyhow, the doctor ran a chest x-ray and CBC, since I had the fly about two or three weeks ago.  He ruled out pneaumonia, and said the blood count was on the low range of normal, so I had viril bronchitis.  

But then he asked if I smoked, and I told him never.  He said he had asked because in the chest x-ray my lungs were hyperextended.  What does this mean?  He muttered that it wasn't anything to be concerned with at my age (I'm an otherwise healthy, non smoking, non drinking, no caffiene 26 year old female).  But I was curious as to what a hyperextended lung was.

Thank you.

[National Jewish]

He probably means that there were areas in the lung that were "hyperinflated". This usually means that air is being trapped in small airways. This is probably associated with whatever reason sent you to the doctor in the first place. It can be due to a virus. In the short term, it really does not mean anything serious and most likely, from what you described, will go away once you are feeling better. This same finding is seen in the lungs of chronic smokers.

[Wildfire Girl]

Thank you.

I have another quick question.  Could this also arise from breathing in chemicals?  Two days before I went to the doctor, I breathed in a heavy dose of cleaning chemicals, which caused a lot of coughing.