Most likely you have data corruption, which is not a bug or virus, but basically code that is not letting the device hardware, software, and firmware communicate. Usually these issues stem from 3rd party applications. My suggestion would be to take your device to an Apple store and let them run a diagnostic on it just to make sure your bluetooth is indeed working properly. Make sure your photos, contacts, notes, etc are backed up to your computer or to some sort of server because the most probable fix will be to wipe the phone itself and port everything back over manually, as any issue will just be brought back over from an iCloud or iTunes backup. These sort of things happen with Apple, Android, and every other kind of device. It's not an Apple specific issue, as my brother has the same issue with every Samsung, Motorola etc phone he's had.