I am petrified after a routine physical. I am told I need a cat scan after a chest x-ray showed a "nodular density." The Dr. says it is still there after the first x-ray showed a shadow in 1/06. Why she didn't tell me to get a cat scan in 1/06 after it first showed up, I don't know. I smoked for like 20 years and grew up in a house of second-hand smoke, but I haven't been smoking in like 3 years. I have no symptoms with the exception of this: I discovered I was very allergic to a friend's dog and whenever I was over there I would have massive coughing attacks. I no longer see the dog and the attacks have subsided for the past 2 months. Could these allergies and cough attacks cause a nodular density? Please help, I am very scared.