@bleuscootergal- Hi. It could be that you need a little help to get your nasal mucosa function/moisture back to functioning pre-sinus infection. This represents a sign of irritation/inflammation if you had not felt it ever before. The lining/function in your nose provides moisture/humidification and changes rapidly to inhaled air. The delicate tissue in your nose might need a little boost getting back to optimal health after fighting off infection/imbalance. The inflammation in nasal mucosa can stick around for a while after an infection. Your body might have had to use a lot of resources to fight off Covid. Assuming while you were getting over it, you were probably inside a lot with dry air. Dryness brings on the cold feeling when inhaling. Focus on Vitamin/Mineral replenishment specifically Vitamin C and Vitamin D, Humidification and lots of hydration. Try to stay a way from forced indoor heat.
Some people naturally experience this feeling, yes, in transient situations of outdoor cold air and or being around dry air. This is due to everyone’s sensitivity being different, nasal mucosa thickness and normal function. If you are only noticing this suddenly and can pinpoint the start of it, then restoration is key when it first begins. Too long of drying nasal mucosa(tissue lining) can damage the little cilia in the nose needed for proper function..