Re: Cooling Fans run at full throttle at Windows 10 Lock Scr
Well, that's definitely not the common behavior, but at the moment it is impossible to say if it is really a problem.
Most probably you have some piece of software, which is configured to work while user (you) is away. And there's no better "trigger" (to tell PC that you are not using it) than locking your PC. The software which runs might be some file-sharing client, crypto-currency miner, some "optimizer" of whatever. It might as well be a virus/malware...
I don't advise you to panic, just check which apps you have installed, which of them are set to auto-run, which are actually running (Task Manager).
Of course run an antivirus check. If you don't have a third-party antivirus, at least use Windows Defender.
There are about +100 other options you can choose from, but start with those above, and we'll move from there once you find (or don't) something.