Why is my speaker volume not working!

So I just replaced my phone bc when I plugged in my headphones the sound would sound like static. I thought it was my headphones so I bought a new pair but they did the same thing. So I figured I blew my speaker and got my phone replaced (I have an iPhone 5s). But

The phone is having volume problems too.

I'm plugging in my headphones but there's no sound at all. I tried playing it out loud but still no sound! It makes the keyboard clicks and the lock sounds even my ringtones when u get a text or call but no volume when i try and listen to YouTube or watch my online TV shows. And it worked last night so I don't know if it fell or something happened to it in the night but my volume isn't working now. I've turned it on and off the volumes on and up all the way. Do I need to go get it replaced again?