My chest x-ray showed biapical subpleural scaring. mild chronic interstitaa changes in lung bases. what does this mean?

Nonspecific: Over time, the lungs may be exposed to many things including inhaled irritants, bacteria/viruses and even stomach acid in people with reflux. Over time, some scarring can develop in the lungs as a result of these insults. What you describe sounds like these types of changes, though you should discuss with your doctor to be sure you don't have some ongoing interstitial lung disease.

See below: Bilateral apical pleural scarring is a common change with aging and not associated with other disease. It should be differentiated from cancer, prior infection or trauma. Lung base interstitial changes may be from atelectasis due to suboptimal inspiratory effort or from fibrosis. A pulmonary physician consult may be useful if you have fibrosis on a ct study.

Old infection: Apical pleural thickening can be result of previous infection such as tuberculosis. It usually means inactive disease. Can see physician for possible TB testing.