Lovely lot of gaslighting the OP going on here.
I'd do one of the following:
Go to queue up until he is in line behind you then remember something you left in the car and go back for it. Bonus points for exclaiming something that only half makes sense as you do so
Act WEIRD. Jitter, dance backwards and forwards seemingly oblivious to his personal space, feet and your handbag bumping and shoving around at groin height.
Act normal but when he coughs deliberately step back onto his foot HARD. "Oops I'm sorry I startled when you coughed in my ear..."
When you go to queue up look him square in the eyes and say loudly in front of others, "please stop queueing next to me, it seems to result in you getting in my personal space and coughing with your mouth uncovered every time, and I don't want to be coughed over."
Large golf umbrella with a pointy end. Carried under your arm pointing backwards to force some personal space. Preferably with some unpredictable accidental swinging as you turn. If he says anything tell him "yes best not stand so close" "It's my new top secret hobby." Again, don't be afraid to come across as weird.