My trackpad button is stuck.

You can simply replace it. To do so, you need to be little bit careful since you are taking couple of parts apart.

Buy the right part first. You may need a iFixit's Bit Driver Kit because the battery screws and the screws of the trackpad are of different birth and you will not ruin it once you are up to it. As the parts arrive, pen the rear case. Disconnect the battery from the logic board. Pull the battery out. Pull the trackpad out and replace it with the new one. Don't lose the tinny 4 screws that hold the trackpad. When you purchase the trackpad, it may/mayn't have the screws included (depends who you buy from). That's it. Be careful not to drop trackpad over the display which may break it.

Let me know if you successfully did it. It's a bit fun too. Saves great wallet.