I've never seen or heard of anything like that happening on someone's device other than yours. Is your device jailbroken? If so, could a tweak be the culprit? If your device is not jailbroken then I highly recommend that you put your device in
DFU Mode, connect it to your computer and then initiate the computer's iTunes app (preferably the latest version). Make sure the computer is connected to the internet. Now when iTunes detect your iPhone 4S in recovery, select to restore and update. After the process is complete, set up your device as new. This procedure will give you a clean slate so be sure to backup photos, music, videos, documents and other data beforehand.