Champ freezing

I have a problem that's really starting to bug the hell outta me. so its happening randomly now, but the problem is my champ freezes randomly during game. the minions move every other champ moves the game goes on smoothly my ping is good fps is good. i just freeze and cant move or cast any abilities and now i cant even lock in during champ select. i really really need some help its tilting the crap outta me.