Hi.. Since you have been smoking, you may be having COPD changes that could be the cause for the cough as the doctors had mentioned.. Infection usually have fever/weighloss/appetite loss and so on which you do not have hence it is unlikely due to infection.. But you need to know the reason for blood in the urine.. Get a perrectal examinationt to look for the cause.. You can take a second opinion too from a specialist, if you are interested...