Welcome to the MetaMask Community @Maikel!! 
You can use the Binance Bridge to move your tokens from/to BSC and ETH Mainnet. You will need BNB in order to do so.
You should see an estimated gas fee prior to completing the transfer. Check that you have sufficient tokens in your wallet before doing so.
You should then be able to connect your MetaMask wallet to Uniswap and complete your swap. Let us know if you continue to receive errors. Screenshots are helpful!