The change in environment (going to maryland) could have triggered a worse-than-usual allergic reaction. If you traveled by plane or bus, you could have also picked up a virus. After a chest xray and CT Scan, I'd say you're pretty much in the clear. This will gradually go way. You failed to mention if your cough is productive (any sputum)?? If there is, it means you're trying to bring something up. OTC Meds that contain guifenesen usually help because they contain an expectorant which helps you clear the lungs. I'm sure you'll gradually see an improvement. Be Blessed!