||Hey Burnt Pancake,
Your issue sounds similar to those that load League of Legends with another program.
For example, Steam. The overlay in a program like Steam has been known to cause control issues with our game.
If you're doing this, I would encourage you to try loading LoL by itself.
If that doesn't work, let's try loading LoL in Borderless Windowed Mode. You can do this by launching the game, and going to Video Settings. Then select Borderless Windowed Mode.
With that said, it's possible these won't fully resolve your issues. If you're still running into problems and not finding the answers you need here on the forums, you should contact one of our Tech Specialists. You can do so at this link: