If that is correct, the course of your illness is consistent with what is called, Community Acquired Pneumonia
(CAP -- pneumonia
acquired when not hospitalized). There are many causes of pneumonia (bacteria, fungi, viruses, chemical or organic irritants) and, even with extensive bacteriologic testing the specific cause is often not determined. The information you have provided, including the imaging studies (X-ray and CT) provides no clues as to the cause of your pneumonia.