When the chest x-ray is said to show a scar, that is exactly what it usually is, a scar from a lung infection sometime in your past, often distant past. The standard chest x-ray is ordinarily not a sensitive way to make the diagnosis of emphysema; it can be suggestive. You will need the CT scan, as ordered, and complete pulmonary function tests (PFTs).
If the tests confirm the diagnosis of emphysema, you should never, ever smoke again and your doctors should check your blood for an alpha-1 antitrypsin level to see if you and other family members, including children have an inherited weakness that could result in emphysema at an early age.
BTW, I'm now 39 having smoked for the last 20 years. Taking Chantix since I got out of the hospital abd should be all quit in a few days.