Why does my volume/ringer locked on the highest sound? Htc on m8

[3user]

I've had my m8 for a year and a half and recently my volume is locked at highest profile. If I try to lower it to put it to silent/vibrate the ticker will either stutter of go back to the highest profile. If I hold the volume down key the ticker will stutter and reboot. It's been like this for a while but I used an app to silence my phone, but now if I turn off my phone and turn it back on it will reboot after 1 minute or so. Can I send it to htc or att to have them fix/replace it? Also my phone is rooted and s-off.