IPhone 4S Sound problems

My iPhone 4S has been having some serious issues lately. The phone refuses to play the audio of any form of media, in-app sounds, music, or YouTube videos. There won't be any sound whenever all those things are being played. However, the alarm works fine, and it rings when I receive calls.
I saw that the volume "knob" has disappeared. You know, the volume control when you double-press the home button and swipe to the right? The volume bar is there, except that it's empty, and the little circle to change the volume is completely gone. It's become really annoying, and the only time it'll play any audio is if I plug a earpiece into it.
The Ringer setting is gone too. When I try to adjust the ringer volume, the icon appears on the screen, but the denominations of volume is also gone. The little white boxes? Yea, they aren't there anymore.
All this happens both in Silent and Normal mode. Airplane mode is off, and as far as I can tell, everything else is normal.
So can anyone tell me what the problem and how to fix it?
If not, I'll have to take it to the darned apple store.sigh*

Sounds like a software problem to me not hardware (thats a good thing). Try resetting the phone as a first resort. To do this. Hold Down Home and Power buttons until the screen goes dark and it turns off. Then turn on like normal. If that doesn't work try restoring in iTunes (BACKUP FIRST) Restore as new and see if problem goes away. If it does now restore again except this time from the backup you created. (This is all in iTunes instructions are on Apples website) If it doesn't work however, theirs something wrong with the phone and it needs to be taken to the apple store.

I need help with my iPhone 4s sound it works but wen I go to YouTube to watch videos the sound doesn't work but wen I click the sound options button it only says Airport express and dock connector not iPhone please help