coughing for 2 years

I am 26 and have had a dry cough for almost 2 years. I do not smoke. when we moved we found alot of black mold behind a bookcase and a window covering. The mold coved most of the wall. We moved to az that week. I was told that the dry air of  Az was makeing me cuogh and have nose bleeds. we moved back to Ok  and i still ccough every day. i had a chest x-ray and was told i had bronchitis. I have be givin amoyicillin, cefdinr, guaiphen-d, propoxy-n/apap, azithroycin, hisinex hc syrup, aluterol.when the cough did not go awaythey siad i might have asthma and was given  prednisone, proair, flovent, fluticasone nasal spray. My scores to see if i had asthma are in the high 90's( 98,96,95). I still cough but not as often about 50 % less. What could be making me cough? Should i have a blood  test done?      

[National Jewish Health]

Chronic cough can be from many things, asthma being only one of them.  This can be from allergies, from sinus inflammation and/or infection or chronic bronchitis.  Having one person direct the evaluation is important.  Since this has been going on so long and persists despite all of the medications you have listed, it might be a good idea to have a specialist lead that evaluation.  You may want to see a Pulmonologist or an Allergist next to evaluate what is happening.  A CT scan of the sinuses may be one of their recommendations to see if this is the cause.