I was unable to make any transactions for pancakeswap, so I decided to join a group on their telegram to ask. Someone stole my security keys and stole all my coins. Now I want to know if I can change those security words so that the person no longer has access to my account and I can continue using it.
Welcome to the MetaMask Community @lukazedu!! 
I am very sorry to hear this happened. Unfortunately, it is not possible to change the seed phrase associated with a wallet. We recommend you create a completely new wallet, transfer any remaining tokens to your new wallet, and completely abandon your compromised wallet.