There is a bug with Oculus being installed that can cause audio to not work in PC mode versions of VR games. Sometimes restarting your PC will fix this, if not you can try disabling the Oculus audio device.
If that does not work you can try the steps in this article. Personally, Method 4 on this link worked for me
https://www.systweak.com/blogs/no-sound-steam-games-windows/