A nodule is usually seen as a round shadow in the lung on a chest x-ray. When definitely calcified, a nodule is deemed to almost certainly be benign, most likely a residual of past infection. Nodules are seen with a wide range in size; the larger ones of greater concern. A non-calcified nodule can be either benign or malignant, more likely to be benign if it is small, less than 1 inch in diameter. Other characteristics of the appearance of the nodule are taken into account by doctors, especially radiologists, when speculating on the nature of the nodule. You should definitely ask your doctor to provide you with the most likely diagnosis based, not only on nodule size, shape, regularity of surface, that is to say on appearance, but also based on your age, smoking history, part of the country you live in etc. You should ask for a copy of the radiologist's official report.
The very first thing however, is to obtain all available prior x-rays, to determine if the nodule was present in the past and either not noted or not commented-upon.
Thank you so much for the info.