Typically, the presenting symptoms are recurrent respiratory infections, like bronchitis, sinus infections, and even pneumonia, usually at a young age. However, there have been cases where cystic fibrosis hasn't been diagnosed until later in life. A productive cough with a lot of sputum, or mucus production, is really the hallmark of cystic fibrosis. You might also experience shortness of breath, wheezing, and chest discomfort.