Do you have two mic's? Like one on your camera and one on your laptop?

It could be from a number of many things. Here's a list of things you can check on. Mute your own stream. Turn your music down so it doesn't feedback. Open the Stream Master obs and under Audio Mixer find Mic/Aux (scroll down if you have to) click the 3dots then Advanced Audio Properties - Make sure it says Monitor Off. Monitor on - means you will hear it through your headset if you are using one - or your tv. If you stream from the CB site directly then try the OBS. If you stream from OBS then try streaming directly. To figure out where the issue is coming from. If you get it from both, then your problem is in your system. Would need more info from ya to properly diagnose it. Hope some of this info helps. Good Luck