Interesting that you mention a CT scan. I had sinus issues for so many years that I stopped noticing that breathing through my nose wasn’t generally easy; not completely impossible but just difficult enough that I had more or less just switched over to breathing through my mouth. I was diagnosed with mild sleep apnea 2-3 years ago and settled on a full (nose + mouth) mask to wear at night. I casually mentioned to my sleep medicine doctor that I really liked the mask because it allowed me to breathe through my mouth and still get the benefits of improved sleep. He looked at me with some concern and said “what do you mean you can’t normally breathe through your nose? That causes several problems”. A followup with an ENT doctor and a review of a years-old CT scan of my head led to nose surgery (septoplasty, significant nasal turbinate reduction, etc.) which dramatically improved my ability to breathe and in general led to a reduction in noticeable sinus infections.
Fast forward to last September. I had a fall at home that included a severe blow to my head - I was dizzy, nauseous, and bleeding out of my left ear. A trip to the ER followed immediately and it included a CT scan. No swelling or bleeding inside the skull but still a concussion and I needed 12 stitches in my left ear. The ER doctor started to ask me about sinus infections and if I had one right now. This seemed to my wife and I that it was a really random thing to be asking about; I insisted that as I had no symptoms of one (breathing freely, no coughs, no post-nasal drip, etc.) that I was sure I didn’t have one. He then says “well then, there are a few things that showed up on the scan that are concerning to me”. Remembering that there was an earlier scan to use as a baseline, we agree that the new scan would be sent to the ENT doc I had seen for review.
It would turn out that I had a large chronic sinus infection that I was utterly asymptomatic for. The treatment since then has been daily budenoside + saline rinse. Unfortunately a followup scan showed that it is remarkably resistant to treatment although there is some improvement.