iPad4 volume button appears to have suddenly gone bad, will not increase volume. Has anyone else experienced this problem?

My iPad4 lives in a smart case, it never even goes out of the house. I baby it to be honest. So why, I ask you, did the volume button suddenly stop working? I tried all the suggested software and general settings I could find but it appears to be a hardware issue. I hope I'm wrong. I can decrease volume down to mute without effort but the volume 'up' function is totally kaputt. Maybe somebody has experienced this problem and found a solution? I'm bummed that my (otherwise) perfect little iPad now has an annoying flaw. - Thank you