Well, now that depends. You don't REALLY mean the button is stuck, do you?

What you mean is that the spoiler won't retract. Right? In THAT case, it CAN be as easy as a blown fuse for the motor. OR it can be a bad motor. The odds that the Body Control Module is bad are kinda low, I've never heard of one dying such that the spoiler not working is the only symptom.

Oddly enough, a spoiler with a mind of it's own is often (are you ready for this?) - a flaky (can you guess?) battery.

One of the members of our Facebook page had issues with the spoiler and when they took the cover off the bottom of the trunk lid, they found the little drain hoses had been leaking and the motor and limit switches were wet and corroded - a new one on my and I've been here since 2009. I DOUBT that is it, but you never know. Just taking the little pop-in anchors out and the Torx screw under the emergency release handle is all that is needed to gain access to what's under there. Might be worth a look. Oh, wait - that was a Roadster - I have never owned a coupe - is the drain system similar in a coupe? I have no clue.