Positive PPD test, negative chest x-ray, but persistent cough and symptoms - TB?

The chest x-ray after a positive skin test is all that is needed. This is all probably allergies and taking some allergy medication regularly may make this go away. It might also be possible that you may need to try several different allergy meds before you find the right one. Many people have trouble like this when moving to a different area of the country and can take a year or more for your body to become acclimated to the region you are now residing. The drainage down the back of your throat constantly would cause the congestion and cough for this length of time. The goal would be to stop the drainage which would, in turn, stop the cough.