IPhone 4S acting up, no sound?

Well, my phone has been acting weird lately. It won't let me change the volume and it's acting like it's on Bluetooth but BLUETOOTH IS TURNED OFF. It won't make sound when I plug in my headphones either. I have no idea what's going on and I really need some help here! I've checked, it's not on silent or anything…

It seems like your iPhone needs a full-restore (don't worry you won't lose anything)

BACKUP:
1)Connect your iOS device to a computer with the latest version of iTunes installed.
2)Open the iOS device's Summary tab.
3)Click the Back Up Now button.

RESTORE:
1)Connect your device to your computer.
2)Select your iPhone, iPad, or iPod touch when it appears in iTunes. Select the Summary tab, and click the Restore button.
3)Click Restore.
4)After a restore, the iOS device restarts. You should then see "Slide to set up".
5)iTunes will ask you if you wish to restore from a previous backup - select your backup and click continue.
6) Your device should restart and everything will be there

If the problem persists contact Apple

On you phone go to settings then general them reset then press reset network settings it won't delete anything it will only delete your Wi-Fi codes you can always put them back in though no big deal