Check this out ... Justin Bieber's new single, "It's Working," lyrics which refer to someone how knows "exactly what to do to hurt me."

After all the on-again-off-again between JB and Selena Gomez, it seems the single may be a message to his ex. And then this ...

Selena posted this selfie four days ago. Just what she means by "taking my power back," we're not sure, but we're guessing it has something to do with the Biebs.