What Could Be Causing Recurring Shortness Of Breath, Given The History Of Childhood Pneumonia And Nose Surgery?

Greetings, respected doctor. I need medical advice for my 25 years old son who is suffering from breath shortage ( hard to breathe). He is healthy otherwise and a good sportsman as well. He had a pneumonia issue in his childhood and since then having a breath shortage problem every now and then. He had undergone nose surgery as well. He is not using any medicine at all.