It most likely came off the track. Have someone hold the button to roll the window up, while you are trying to pull the window up.
If that doesnt work try the same thing just pushing the button to roll down, you might have to push down before you can roll it back up, May cause the window to fall all the way down (happen to me and I needed to get get pliers to pull it out)
If you window is off the track you will probably need to take it apart to get it back on. Hopefully your window motor isnt out as that can get pricey.
Same thing happened in my car not long ago but both back windows went out... and they wanted 350 for motor and labor per window.