Welcome to YT!
It sounds like reverse sneezing and Georgie does that when he gets excited or when he drinks water to fast so I think it's completely normal. If you search this forum on reverse sneezing you will find a lot of information. At the next vet visit ask your vet just to put your mind at ease. I would also ask them to check out the knot.
BTW it's ok to be worried I know Georgie is 6 and I still worry.