Hello,
You do have a mastering plug-in in your master bus. After you bounced your mix into an audio track inside Sonar, are you deactivating all plugins in your master bus for listening to your mix? If not then you're running your mix through this plug-in twice. I also assume that your having your gain set to a value lower than zero in your master bus. That could be the reason that your mix is sounding lower in volume when you're listening to it after bouncing, because you're listening to your mix through your master bus, which has a gain lower than zero.
Regarding the "explosions": did you ever check your system for audio problems with this tool: https://www.latencymon.com/ ?
This is highly recommended. There you can see if there are problems on your machine that are not related to your DAW and are caused by your operating system and configurations.
Cheers
Jochen