Occaisional ankle issue, since childhood

When I used to enjoy cross country running at school, almost every time I began running, my left ankle would seem to click after a few steps, leaving me hopping for several steps on on my right. Once over that, all would be fine until the next time I began to run. What would seem to happen, was the flat of my foot would seem to want to turn over, so that the flat of my left rolled to face the right foot somehow/ little toe down, big toe up - or so it seemed.

As an adult and now too old to run, without warning I seem to very occasionally get the same sort of pain in the same ankle, but rather than immediately going, it remains for a few days as right now. It showed up again a couple of days ago - my ankle seemed to turn over, immediate pain, since when I have been hobbling round trying to nurse it. I can put my weight on it, can walk on it, but with the constant worry about it giving way again without warning. Walking on tip toe, seems better than walking heel down first. With no weight on the foot, deliberately twisting the flat of the foot to face the right, causes some pain. Rotating the the foot in a full circle causes me no pain.

At the moment I'm going up and down stairs by locking my left ankle, clinging to the bannister and taking the steps one at a time.

There is no sign of swelling, no visible bruising.

As it happens so infrequently and reasonably quickly resolves itself, I have never sought any medical help, but I am curious as to the cause and ways to avoid it.