No sound PC to Phone

So I've started doing YouTube a bit of time ago, and I wanted to record my Phone's screen.
So I've gotten Quicksupport on my phone and then connected to my phone from my PC.
Later on, I've realized the fact that there was no sound coming from my PC's speakers that was also playing on my phone, so I went to check the recording and to my expectations, no sound.
Please tell me why this has happened, thanks!