Context

This line is written by Luke in Luke 4:23.

Jesus says this around the beginning of his ministry when he's teaching in his own synagogue and nobody will believe that he's the real deal.

Basically, the phrase "Physician, heal thyself" is a way that a person would ask for evidence, showing why they should have confidence in someone else. So Jesus is using this line to tell them that he already knows they don't trust him, and are probably going to hit him with that proverb at some point.

Where you've heard it

This is kind of another way to say, "Look who's talking! You think I've got problems? Worry about your own, buster!" It's also often brought up in an ironic way when talking about healthcare, for obvious reasons, like this article, or this article, or even the last line of this one.

Pretentious Factor

If you were to drop this quote at a dinner party, would you get an in-unison "awww" or would everyone roll their eyes and never invite you back? Here it is, on a scale of 1-10.

This one could be a close call, but it's short and punchy and over-the-top enough that it's actually fairly safe.