I have a 2 mm solitary pulmonary nodule. Is this serious?

Hello doctor,

I am a 74-year-old male, weighing 142 lbs, height 5 feet 10 inches, and a non-smoker. I worked in an auto body shop for two years and painted cars for 18 to 19 years. Had minimal exposure to asbestos and quitting grain farming at the age of 44 years. When I was 56 years old, I had a severe panic disorder and MVP. Around three months ago, I had a very small amount of blood in my phlegm when clearing my throat about six times. The doctor said that it was due to a blood vessel breakage but ordered a pulmonary function test and chest CT to be sure. The pulmonary function test done two months back was normal. Chest CT findings showed no bronchiectasis or interstitial lung disease and no pneumothorax or pleural effusion. There is very minimal atelectasis in the left and right lower lobes. There is a 2 mm pleural-based RT, lower lobe pulmonary nodule, and no additional nodule or mass. My pulmonary doctor said nothing was seriously wrong.

What is your opinion? Should I have follow-ups on the 2 mm nodule? What did minimal atelectasis mean, and what caused it? I take no medicines except Ativan PRN.