My iPhone 4s stopped making sounds the other day. Yesterday it turned itself off and I had to do a hard reset to get it to turn back on. For the past week it's been having little fritzes of wonky sound when opening Apps that I have the sound automatically muted on, where it'll play the sound for a second and then the volume-adjust image will appear and go muted. When I try to change the volume it gives me a picture of a bell, but none of the volume adjust bars come up and it does not say my headphones are in. It also is not in Do Not Disturb mode. My sound settings are normal, and it plays my ringtone when I adjust from the settings, but will not play any sound otherwise. I updated it to 9.1 about a month ago and it's been much slower since, as well.