Can a tfcc tear fully heal on its own or does the pain eventually subside while the tear remains?

Tfcc: Possibly, by wearing a splint or cast for 4-6 weeks.

TFCC Tear: Generally speaking if the pain has resolved and the wrist is stable (i.E not loose on exam), then you should be ok. There are certainly situations where the tfcc is not fully "healed" but symptoms resolve. Typically these can be left alone, though it it certainly possible for symptoms to recur, dependent to some degree on your activity level.

Usually no: Joint environments are very avascular and no blood=no healing. Which is why acl tears are reconstructed rather than repaired (ligament replaced). So a tfcc tear will typically not heal, but that doesnt mean that the pain wont go away. If the pain subsides, good...If it doesnt then would go in to be seen. Usually by a hand surgeon.

Good question: The pain can certainly go away when the tfcc is torn. Some tears go through an area with poor blood supply that does not heal, but still get better with time. No real answer. Think about the patients who had tfcc tears before MRI and arthroscopy. At least some got better on their own. If mechanical symptoms last, surgery is appropriate.