1. Air conditioning
2. Air quality changes
3. Temperature changes
All three of these factors are common sense to most of us but we tend to forget the truth behind what causes this issue for so many. It never fails, every winter; spring; and fall. I get sick with a sinus infection. It's not because I'm unhealthy because believe me; I'm in better health than some people my age but it's a lot to do with those three painful factors of life at which I posted above.
Honestly, I wish sickness didn't exist but if it's didn't...a lot of doctors and surgeons would be broke...so I guess we just have to accept that it's part of this endless journey we're taking in life.
Here's to getting well soon!