volume on my ipad stopped working

Are you having difficulties with the physical volume buttons - or all volume controls, including those accessed from the Control Centre (swipe downwards from the top-right corner of the screen)?

If you have software issue, a forced restart of the iPad will often resolve the problem:

• On an iPad with a Home button: Press and hold the top button and the Home button at the same time. When the Apple logo appears, release both buttons.
• On other iPad models: Press and quickly release the volume up button, press and quickly release the volume down button, then press and hold the top button. When the Apple logo appears, release the button.