Perfectly normal for a Quad Core CPU. You're utilising each core and thread more in order to both game and stream. Asides - a "general" overall package usage of 100% could mean any 1 core is peaking.
At this point - it's more important that you're keeping your components cool if they're at peak usage a lot.
If you want to lower it, you'll need to modify your gaming / streaming settings. Or otherwise just see if there is anything else hogging resource.