<s>[INST] Have been complaining of shortness of breath and chest pain. Cardiac work up negative. Pulmonary findings sleep apnea. Chronic obstructive lung disease. Had chest xray which states coarsening of the interstitial markings. Trying to understand. What does this mean. [/INST] Hi welcome to the health care magic Interstitial marking coarsening can be seen in interstitial lung disease rather then COPD.... For COPD confirmation better to investigate with pulmonary function test esp. Spirometry... In pulmonary function test  FEV1,  FEV1/FVC,  FVC,  DLCO etc like investigations will be done... And this pulmonary function test able to differentiate between COPD like obstructive problem and restrictive lung disease like pneumonia or interstitial lung disease Smoking is most common cause related to such problems Hope your concern solved Consult pulmonologoist for examination and pulmonary function test (if needed after examination) Take care </s>