Why is the sound on my Samsung GalaxyS5 changing from max to mute uncontrollably??

[AC Question]

Been happening for the past month and a half, I just thought it was me accidentally touching the volume button and the button was just sensitive but that's not the case. I set it down and just pressed play on my music and it started going wacko without me even touching it. What can I do to change this? I've tried to change a couple things at a time in the settings but haven't seemed to get it to work.