You have no sound at all in the Music App?
Is the volume turned up - as simple as that sounds - I have seen users not realize that the volume was turned down. If you have sound in the Music App but do not have app sounds or keyboard click, email notification sounds and the like, system sounds are muted.
System sounds can be muted and controlled two different ways. The screen lock rotation can be controlled in the same manner as well.
Settings>General>Use Side Switch to: Mute System sounds. If this option is selected, the switch on the side of the iPad above the volume rocker will mute system sounds.
If you choose Lock Screen Rotation, then the switch locks the screen. If the screen is locked, you will see a lock icon in the upper right corner next to the battery indicator gauge.
If you have the side switch set to lock screen rotation then the system sound control is in the task bar. Double tap the home button and in the task bar at the bottom, swipe all the way to the right. The speaker icon is all the way to the left. Tap on it and system sounds will return.
If you have the side switch set to mute system sounds, then the screen lock rotation can be accessed via the task bar in the same manner as described above.
This support article from Apple explains how the side switch works.
If you have absolutely no sound at all in any app and the volume is turned up, try rebooting your iPad.
Reboot the iPad by holding down on the sleep and home buttons at the same time for about 10-15 seconds until the Apple Logo appears - ignore the red slider if it appears on the screen - let go of the buttons. Let the iPad start up.
Really obvious I'm afraid but please check Settings> Sounds Change with Buttons set to Off? If so only Alerts will be controllable with the volume slider here. Try turning on and raising volume if necessary.
Also as a good check, in the same screen are keyboard clicks set to on? If so open Notes and start typing can you hear anything?