sound is not working on iphone ?

Okay so this started agesss ago when i downloaded ios5? I figured that when i updated the software it would be fixed! But no unfortunately. Anyway the problem is that the sound on my iPhone 4s randomly stops working! Alarms still sound but thats it. I can try and adjust the volume but when i press the volume button the speaker picture shoes but none of the white dots to show that the sound is turning up. Same with when i try and slide the volume up, theres no slidey thing there.  Is there anyone that knows how i can fix this!? ...Answer