Ve been diagnosed with pulmonary fibrosis, sometimes I have pain in the breastbone, could it be related to pf?

Not directly... Pulmonary fibrosis does not cause pain directly but if you are coughing, the cough can lead to musculoskeletal chest wall pain. If the pain is present all the time (not just when coughing or deep breathing), see your doctor to be sure it is not cardiac pain.
Unlikely. Pulmonary fibrosis/ ipf is usually a painless process. Breastbone pain in the illness is usually associated with muscle pain from the chronic dry cough that accompanies ipf. If your fibrosis is secondary to an underlying arthritis like rheumatoid your breast bone pain could be secondary to inflammation in the join between the manubrium and the sternum (two individual bones of the breastbone).
It may be. But the substernal pain may also indicate some heart issue which are common with pulmonary fibrosis especial diastolic dysfunction, but atypical chest pain related to the fibrosis also can occur. Suggest you have it looked at by a physcian.