I think you should be checked by a lung specialist. I had never heard of Interstitial Pulmonary Fibrosis until my husband was diagnosed. He had a persistent dry cough for over a year. Initially, it was put down to acid reflux until a very astute GP heard crackling and asked for an x-ray of the lungs. My husband has never smoked. After many tests, etc. it has been established that his IPF is as a result of his autoimmune system attacking his good cells.