In reply to Rob Laird:
Do you also have pain whilst engaging the outer ligament and rotating, or whilst the wrist is under duress and rotating?
It could be anything from a micro fracture, to a strain of ligament or anything in between. The wrist area is such a complex part of the body, with lots of bones and ligaments. Get to your GP ASAP!!
I currently am at my forth specialist after being referred all over the NHS for such an injury. They still have no idea what is up, and maybe looking to microscopic inspection. I've been waiting for a full diagnosis for over a year!