I'm 3 days shy of two years cancer free and still have minor issues. When I get choked it's usually right after doing something stupid like a huge bite, no water (or beer) or getting cocky and trying to eat something I KNOW will give me trouble. Two things that have helped are what I call the weight lifters swallow: breathe in and then swallow overly hard like you're forcing something down. Also a slight turn of the head to one side sometimes helps.
Good luck and keep fighting!!