IPhone 4S my ringer isn't working?

I can hear sound with my headphones in, but I can't hear sounds at all without them. I tried to press the volume buttons without my headphones but it doesn't work and all that shows up is "ringer" and nothing else like it's stuck or something. What's wrong with my phone? What can I do to get the sound back?

Backup and restore

Hiya! Until recently, the exact same thing used to happen to me and I could never figure out why! It was so frustrating… But then my sister informed me of a little switch on the side of the phone! You can shift it up and down, and if you can see red, that means it's on silent mode -if not, (if it's switched up) it should work fine. Hope this helped!

This happened to me a few months ago. And I'm almost positive it's not the mute switch. Most people know about that. It's not hard to figure out. Lol. I fixed mine. I'm not sure what really causes it, but I kept turning my phone on and off. Then I did a reboot. ( hold the power button and the home button at the same time until the apple logo appears ) and after I did this a few times it finally fixed it. I don't know what makes it do this but I've heard lots of People have this problem. Apple needs to try to do a software update to fix this. Hope this helped. Good luck! Try looking it up on google and other people may have found the solution. Have a good day!