Speakers aren't working on iPhone 4S?

When I play audio, whether it's from the music app, YouTube, Pandora, etc., my speakers don't make any sound. It's not on silent, I switched it on and off multiple times, and when I use the volume up button to try to turn it up, nothing comes up on the screen like it usually does. Or when I double tap the home button and try to use the slider, it's not even there. The keyboard clicks and unlock/lock sounds don't work, but ringtones do, and text tones sometimes do. I don't understand why this is happening?

Also, my lock button randomly stopped working about a week ago and a few months ago, my volume down button stopped too.

Any ideas?

Almost all of the buttons, volume up, down, mute switch, and sleep button are all on the same cable/connector inside the phone. Most likely this connector has come loose. Take it to your local iPhone repair shop. If that is the problem they can fix it pretty cheap. If not they will give you an estimate to get it fixed.