I developed a chronic cough for many months following an unknown upper respiratory infection, and the chest ct (no contrast) showed mild coarse interstitial lung markings at the lung apices consistent with mild areas of scarring. what does this mean?

How does a CT or any test apply to me? To answer that it should be understood that tests results are taken into account with the things the patients, says, the examination, lab tests, and all other diagnostic tests. Ask your doctor who was able to examine you about your condition. These CT findings are not specific to a particular condition but may be connected to your cough