Is it bad that under very heavy load my CPU Fan starts being very loud?

Like, for instance, I have to play CSGO capped at 60FPS otherwise this happens and I'm scared it won't like burn up in flames..I don't think that HWMonitor is giving me the right temps because it goes up to 105C..and as soon as I tab out of the game it instantly goes down to like 90C..So I don't really believe it. This doesn't happen in all games, but it does in most.Sometimes it starts like 5 mins after the game is launcher sometimes I can game on for a hour and it's okay(and then starts).