28/male. I Am A Non Smoker. I Suffer From Asthma

28/male. I am a non smoker. I suffer from Asthma and GERD. I recently had a chest x-ray due to chest tightness and shortness of breath. The doctor wanted to rule out any infections or other problems. The chest x-ray results were as followed: "Heart size is within normal limits. No adenopathy is seen, there is no consolidation or pleural fluid. Lung volumes are upper limits normal. The interstitium is slightly coarse for age. IMPRESSION: No acute abnormality detected." I am curious to know what the doctor means when he states that my lung volumes are upper limits normal and that my interstitium is slightly coarse for age. I did some research online and everything I found states that a coarsening of a persons interstitium is a sign of Interstitial Lung Diseases like Pulmonary Fibrosis. Should I be concerned with the doctors findings? The only problems I have ever had with my lungs beside Asthma are two bouts of pneumonia, once when I was a toddler and another time when I was a teenager I had double pneumonia. Other than that I have had no other issues.