Using wp8.1,problem in sound with headphone as its right earpiece doesn't work some times but after restarting device both earpieces work fine.seems like a firmware related bug.any solution without hard reset and soft reset.i tried both the ways.
I'm having that problem now with my Lumia 820. I listen to some music from my SD card, and then pause the music and come back in a little while. I lose sound from the right earpiece. If I restart the phone, all is fine. Fortunately, I can get around it, but it's annoying.