The best thing to do is to recall what you did last before all this happened, I'm guessing it could be something to do with extra-decoders package that you may have obtained from extras-devel.

Failing that would probably result in a simpler issue of reflashing your device and seeing if the problem persists.

FYI, no its not normal to see multiple instances of pulseaudio running when your device is not playing anything. I just checked my device and I can only see one thread of pulseaudio.