It happened to me. That's the main reason why I ended up in this board.
My temporary solution (before it came back to life again for no reason, nobody really knew how to fixe this), was to download an app called Screen Off Proximity Sensor (search these words, it will come up on google play store).
Basically it allows you to turn on and off your screen with the proximity of anything to the phone's sensor (the same one you use when you're calling someone). It sucks, indeed, but it's a temporary solution till it gets better again.
I hope this works for you.
(you can set the app settings for how long you which the sensor to be trigged to turn on/off)