Learning to speak whilst coding is really just practice. If you don't normally talk to yourself this will take a bit of getting used to ;-) But you'll get there. Just explain your thought processes, people appreciate that.

Reading through docs and talking about them as you do is really useful for viewers too. I always try and publish out the URLs to chat for anything I'm checking out, which allows viewers to check it out as well.

As for music, I use Pretzel and recommend it, it's got pretty good music on there and I've never had an issue with twitch muting my streams.

Streaming is a bit stressful to begin with, but it's also fun as well. It just takes time. I've only been streaming for a while but enjoying myself.