@alic Lung nodules, especially in people with asthma, or other lung diseases, are commonly "artifacts" of infections, either past or present. Since the second scan showed a decrease in the size, it supports the lung doc's opinion that it is infection - malignant nodules, as far as I know, don't get smaller.

Something else to consider - even if you got a PET scan at this point, and the nodule "lit up", it still could be an infection OR possibly malignant. But 7mm is too small to accurately biopsy, so you would end up waiting another 3-6 months to be checked again.

Only you can decide whether you would gain from having tests done twice.