I wouldn’t rule out a broken scaphoid unless you had an X-Ray 1 or 2 weeks after the injury. And if it is that, you want to get it fixed asap. Don’t ask how I know :(
More recently, I had a similar experience with my son after a BMX fall. He went to A&E and got it X-rayed – all clear. Weeks later I noticed he was often holding and rubbing it and he said it was sore when he did jumps and things. Back to GP for a referral which was a battle to get. After that, X-ray confirmed a scaphoid break that had not been picked up at the time. Cue attempts to heal with a splint for a few weeks – no good. Then cast for a few weeks – still no good. Eventually he had to have op and a screw inserted to pin the 2 halves together.
My recommendation would be see GP and push for a referral to get it checked by X-ray, since if it is this and its not treated you will have real problems in later life as it will not heal.
I don’t know if it will help, but an indication of if the pain is related to a scaphoid problem is to hold your hand as if you are giving a thumbs up, extend your fingers and then press the depression that you can see at the base of your thumb on the back of your hand (the anatomical snuffbox). If there is pain there, that can indicate a scaphoid problem. Use your OK wrist as a reference. Here’s a link to some more details: http://en.wikipedia.org/wiki/Anatomical_snuffbox Check the clinical significance part
Good luck!