Tugget,
Unfortunately, there are a lot of things that can cause wrist pain and decreased range of motion. As you have noted, it is possible that you injured one of the carpal bones before you learned to box properly. And that could now be causing you problems. The most commonly injured carpal is the scaphoid.
But, again, there are many structures that could be causing you problems. There are eight carpal bones (besides the other bones that make up the wrist joint), several tendons (both flexor and extensor), multitude of ligaments holding all those little bones together, the TFCC (triangular fibrocartilage complex), the retinaculum, etc, etc, etc.
So, without a thorough examination and maybe some x-rays, it is almost impossible to tell you exactly what is wrong with your wrist.
If you continue to have problems, you should see a hand surgeon for an evaluation.
Good luck.