Why does my client keep lagging.

Hello everyone first off i would just like to take a moment to say yes i understand some words here are going to be horrible mispelted please work with me here. On to why I'm even making this discussion why does my god damn client keep lagging i have two accounts in the same area one works fine the other is slow and gets me kicked out of games, i have no idea why this is happening and its really annoying as the account that im talking about has something like 400$+ worth of champions and skins so i would really like to be able to play on it. Thnigs ive tried to do to fix it restarting the client it self, restarting my internet and last but not lest restarting my computer to turn off anything that maybe up in the background. i haven't unstailed the game as the other account works just fine so i think its something to do with the host server on this account is there some way to fix this.