Suggest Treatment For Chronic Cough And Shortness Of Breath

I have had a persistent cough with sticky mucous for months and the feeling of shortness of breath. Nine years ago I had something similar and after many tests had a broncoscopy as they were concerned amount a hyditiform mole as I had had a molar pregnancy 9 years before. The doctor said I had a virus in my lungs and that this virus was common in drug addicts so asked me if I was one. Well I was extremely taken aback and said no, that I had never taken unprescribed drugs and even then, would try to do anything before resorting to prescription drugs. He then thought that my immune system should have be able to fight off this virus so then sent me for immune tests which all came back as above normal. Eventually, this virus went away and now it seems it is back. I have gone for a stress test, which was normal, a methacholine challenge test which was relatively normal last year but was told there was some minimal damage to my small airways that might have happened when I smoked more than 26 years ago. I always feel like I am clearing my throat or coughing up mucous and it is really scaring me. I had a chest x-ray April 25/14, which was normal and now am going to have another one as I am worried about lung cancer. I hate to expose myself to more radiation, but don t know what else to do. The problem is, the respirologist has retired and my family doctor at the time is now deceased so I don t even know what the virus was called. Having a bronchoscopy was one of the worst experiences I ever had as I pretty much had a panic attack when they put the instrument down my throat, so I don t know if there is a sputum test that can be done to check for irregularities like a virus or cancer of the lungs. Can you please advise me on this. I feel like I am at my wits end.