You should definitely have the CT scan done. Then ask the radiologist how certain he or she can be that the spot is not cancer. If the CT scan does not identify the problem, and if the spot has not shown up on chest x-rays taken a year or more ago, then the spot will probably have to be removed. Then it can be examined more closely to determine the cause. You are right in assuming that you are at low risk for lung cancer. However there are many other causes of spots. The cause needs to be identified and treated optimally.
If the pneumonia was in the area of the spot, it could have caused the pneumonia by partially blocking a bronchus. This could be seen with a bronchoscopy. During this procedure a tube called a bronchoscope is passed through your nose into your windpipe to look into your lungs. A bronchoscope is a flexible tube with a small camera at one end. With the bronchoscope tiny pieces of lung tissue can be taken for further testing. This is called lung biopsy.