Hi Xenith and thanks for your informative post. I suppose my first thought might be that if this was me I would have gone for a simple wrist x-ray/scan to rule out any fracture of the smaller bones (metacarpals) of the hand. These are often injured when falling in the way you describe and the resultant symptoms might just be a deep aching sensation. I'd want to rule out any issue with the scaphoid bone and although your pain is on the outside of the wrist the change in position of the bones could possible lead to that scenario.

If you did fall more laterally onto the wrist you might have sprained the Triangular Fibrocartilage. This can lead to generalise instability and can be an annoyance, something especially noticeable in people who play tennis and have to grip and hit under load. You might try purchasing a simple wrist wrap and seeing how the wearing of that affects your symptoms. It can be a useful and simple supportive aid to wear for a while to support the carpal bones as a group while the soft tissues heal.

See if you can action either or both of the above and let us know where you end up and we can provide some more insights.
regards
PB