What Does My CT Scan Report Indicate?

Went to the ER with right sided abdominal/pack pain. CT scan states There is a 2 mm, nonobstructing calculus at the upper pole of the left kidney and a possible 3 mm nonobstructing calculus at the lower pole of the right kidney. How can something be listed as possible ? Either it is there or not, right? However, report goes on to state that this does not explain my pain. (no fever, infection, blood in urine, etc...however I did pass kidney stones in 1994 and in 2006). Should I follow up with another doctor other than in the ER?