Eyes squint when strained. For this?

Hi everyone, I used to have a bad squint on my right eye. I got it operated when I was 15. Initially there was a lot of discomfort there was small itching and I used to experience double vision. The doctor said it was common and would subside but even now there is double vision ... I mean it doesn't affect my daily life as the second vision (the one from the operated eye) is lighter and I'm used to it. But even now , whenever I play something like cricket or tennis or any outdoor games for that matter , my right eye goes back to being squint again only to be fine after a couple hours of rest ... the first time it happened, i freaked out and went to see the doc .. only to be told that even this is common and it happens because it's the resting position for the eye ball or something like that. Do I have to live like this all my life ?? Without playing anything or straining my eyes !!! Is there any permanent solution for this ?? Please help