Sound issues on iPhone4s with 7.0.6

Hi, I was wondering if anyone could help me with this...I have this iPhone 4s and the sound randomly stopping working, the text tone and ringtone, along with the vibrate and keyboard sounds as well, and I hard reset the phone and it works again for a bit then it stops working, and I have noticed when this happens the sound on calls ALSO stop working so if i'm in the middle of a phone call it goes silent, I can't hear the person and they cant hear me and I dont know why its doing that, does anyone know of a fix for this or is it hopeless and the phone is just worthless? Thanks for any help!