Hello and hope you are doing well.
The gagging could be due to acid reflux, this can irritate the throat and cause spasms. It can sometimes be a reaction to cold weather. It can also happen due to iron deficiency anemia causing Plummer-Vinson syndrome, where there are changes to the soft lining of the throat. Discuss these options with your doctor when you happen to meet him next time.
Hope this helped and do keep us posted.