I also have those (along with sneezing). I cannot do anything for the next 5-10 minutes until it goes away. For me it's simply (but maybe not only, who knows wh

I also have those (along with sneezing). I cannot do anything for the next 5-10 minutes until it goes away. For me it's simply (but maybe not only, who knows when reading the sibling comments) allergies. I don't have allergy symptoms like cough or watery eyes, etc. But somehow my sinuses get "full" and pressure builds up inside. If I take antihistaminic almost daily then my sinuses (mostly one side) don't fill up and I can't cough or sneeze without fear. Since you went to a doctor they probably ruled that out, but maybe not, and it checks out with their "it's probably mechanical" hunch.