No, no ... don't worry about it. It's a condition called Pulmonary Fibrosis and it is actually rare-ish

It's also not tied to any one fungus, virus, bacteria or whatever. It's just a chance infection of whatever kind that invades your lung system, and causes a run-away reaction with your immune system. The infection turns on the immune system and for whatever reason, the immune system goes haywire and can't turn itself off so it just keeps attacking even after the original infection is gone. It's common in the lungs because when you think about it and study it, the lungs and lung tissue are very delicate and intricate biology that exists in a very narrow balance between being healthy and abnormal. As soon as you upset that balance, its either very difficult or impossible to get it back.

Infections like this can be caused by colds and flus but also from funguses and mold and dust spores. A well known condition is called 'Pigeon Lung' from pigeon breeders who breathe in a lot of dust from pigeon droppings.

I have a doctor friend who warned me years ago .... 'do your best to avoid colds, flus, viruses and bacterial infections' .... even if you are fit and healthy and young. Every infection in your lungs is a lottery and if you get lucky and get infected with something that screws up your system, it will affect your life forever.

My wife got infected with a viral infection on a trip to Morocco about six years ago. We both got sick with it. It was bad but not that bad. I got over it but she just never stopped coughing. A year later she was still coughing and we looked into it and she had lung scarring. The doctors then told us all about these conditions and now she has Pulmonary Fibrosis. She is perpetually coughing, she lives with it but it is a constant worry we have to live with now.

So next time you go out in public remember that any flu, cold, covid, virus, whatever is a lottery that can screw with your life.