Volume button is stuck

I don't know if this will help you since I don't know what caused the problem on your iPad but I had a similar problem with mine. What had happened to me was that I dropped my iPad and the case dented next to the volume button which caused it to "stick" and as a result the volume icon was stuck on my screen.

I tried a few times, unsuccessfully, to pry the volume button back out. The reason this didn't work is because the volume button wasn't stuck at all, the problem is the dent in the case. The only way to solve your problem is to push the dent back out.

The way I did this was to slowly and carefully slide the edge of a knife between the case and the glass and very gently move it up and down to straighten the dent back out. It took a few times before I could remove the knife and the volume icon wouldn't come back but it just takes patience and a very gentle hand.

Be careful because the glass of the iPad screen is incredibly delicate and can break very easily, if you apply too much pressure with the knife it may crack or shatter.

I know some people who have done this with a ring binder clip or their fingernail, I'm only telling you what I used so I'll leave it to your best judgement.

I hope this helps!

Try this, settings> general> accessibility> assistive touch> on.

Tap the onscreen button, tap device> tap volume up or volume down.