Steffen is spot on. You (Liz) jammed the button in too hard and the metal contact probably came loose.
You can get to it without pulling the logic board, but beware, the #1 problem people get into is tearing that power/volume flex cable.
It is possible to get in and take out the two retaining screws holding the metal plate which the power toggle switch is located. Once removed you can use a spudger or other tool to snap that oblong metal piece piece back into place.
You can get easier access to the retaining screws if you lift the logic board per instructions in iFixit (replacing the touch screen), but stay on your toes and DO NOT rip that power cable. I cannot stress this enough. If you tear that cable, your going to have to lift the board and resolder in a new flex cable and without the right soldering equipment and skills can really get into some trouble.
All of the above applies to a "mashed in" volume button as well -- but when you go there it really gets tricky -- you have to desolder the + terminal on the battery and solder in a new cable.