Took my volume issue to Apple Store Tech. As I am out of warranty/no maint plan- my options were to live with it, or pay $150 for a replacement. Appears to be a software problem ( not unique i believe) but no easy solution or fix. I will never know the problem. Worked great for the first 15 months and suddenly this arises. Take great care of the phone and have never dropped it or had it exposed to water. Go figure...