What Causes Constant Pain In Wrist With Normal CT Scan And X-ray?

Hi I have a lot of on going problems with my wrist and I have recently seen a orthopaedic surgeon he has used a local injection to see if it helped with the pain I have been suffering.. the X-rays and mri show I have a larger radius and ulna dimensions then normal. Apparently the normal dimensions are 22cm but mine is measuring 31cm I have been given two options one been to file the bones down to the normal dimentions and the other is to have a plate put in my wrist .. I have constant pain in my wrist and in 18months I have had it in a cast due to it giving way and swelling causing intense pain... The consultant stated that due to the dimentions the bones are grinding together however my question is if I had ulna problems where exactly would I feel the most pain?