I am not pregnant but my left foot tends to swell up like a ballon and looks like it may pop any ideas why?

I am not pregnant but my left foot tends to swell up like a ballon and looks like it may pop any ideas why?

It does not do it all the time but when it does it is painfull. I stay away from salt and food high in sodium I had this when I was pregnant years ago but don't think I can have it when I am not pregnant