Hi helpmeplspls1234,
We understand you're having problems with iMessage on your Mac. We're happy to help.
If you're getting constant prompts to enter your password, we'd recommend completely removing the account from Messages, then signing back in. To remove your account just open Messages then select Messages up in the menu bar > Preferences > Accounts. Click on the Apple ID account that's set up for messages, and remove it.
After it has been completely removed, try signing back into your Apple ID and see if it is still constantly prompting you to enter the password repeatedly .
Use Messages with your Mac
We hope this helps. Cheers!