Ring volume changing on its own.

This morning my phone started switching to silent on its own. It was sitting, untouched, undisturbed, in my purse and I heard the blip, blip noise of a volume change. I have tried turning it off and on, taking out the battery, taking out the battery and the sim while the phone is on, etc. The key pad is frozen and won't work unless you start hitting random keypad buttons over and over..then the ring style screen comes up. You can try to use the side keys to bring the ring style back to 7 and it will go up to 2 and then automatically change back to silent.