Hello Well come to health care magic Really a nice question, what would you do at this point if it were you ? ,i think i would have also posted a similar question in health care magic as you had done, may be some how some where the answer may come out. Any way as your CT findings are suggestive of bronchitis or asthama, then you may first of all try to see if there is any thing that is causing this, like smoking, some perfume you might be using , exposure to any pets, birds or chemicals in your working place or near your residential area, if you could find the triggerer then its elimination will sort out your problem forever.Secondly try to see if you are not taking any medicines that can cause dry cough like ACE inhibitors for hypertension, thirdly you can cosult an ENT doctor to see if there is any cause of cough in upper respiratory tract, may be simply even wax in the ears, get your stool test done for ova and cysts and finally you can consult an immunologist for allergy profile . hope this answer will be of some help to you wish you recover soon and this time compleate full marathion race thanks Dr Arshad