Phone will sound and show volume in phone mode only!

I just bought a new iPhone 7plus and already I'm having a problem with volume. I noticed after a couple weeks it stopped sounding text tones, alerts, etc and even keyboard clicks. Even if I go to settings and choose dif sounds for txts and various alerts, the only ones you can hear are the ringtones. Also, my first clue that there was a problem was when I initially went to adjust the volume. I noticed the bottom sound Level bar didn't even exist. It does however if in phone mode. What the heck apple??