For some reason, whenever I am in a battle, I cannot switch out of my pokemon. I don't know if this is my problem or a problem other people are experiencing. If this is a bug other people are dealing with, I hope we can fix it because this is a pretty essential part of the game

I have this problem as well. Whenever I try, it just sort of rotates the camera and puts the cursor in the middle of the screen. It also gets stuck on the items screen in battle, with the cursor getting shifted every time I try to select an item type or try to hit the back button. The only 'fix' I've found for it is to close the MC window, and remember not to try to access items in battle.

If you are using JEI, Optifine, it might cause the issue. Please ensure you can reproduce the bug with JUST Pixelmon and Forge.