What Causes Pins And Needles In The Wrist And Numbness In Arm?

hi, my names cornelius au.... and about 3 years back i injured my wrist while playing basketball, and i went to the schools nurse and she told me that it was probably a bad sprain and said to check with a doctor just in case. The doctor that i visited in beijing also told me that it was probably a sprain or a hairline fracture..... about 3 months later i was messing with my wrist when i felt something shift ............ and miraculously i could move my wrist again. ever since my wrist has been having this weird sensation that is similar to pins and needles and at times my arm and hand goes numb... to add to this my hand seems to be getting weaker. can you tell me whats wrong with it and how to fix it?