Hi there! I have not purchased Dragon for my computer yet ($$ ) but I have had the chance to use the newest version of it at my college. Due to my physical limitations I am able to access their tech lab for disabled students. There is a bit of learning to do cos you can't just talk as in everyday speech. But I felt that it was good and I would recommend it.
There are others I haven't used yet. I'm told there is one built into Windows but I can't find it
I have found good ergonomic info here http://www.ergoblog.com/ also rsi-relief.com has reviewed several voice program here: http://www.rsi-relief.com/?s=voice+recognition
Good luck with your pain- I hope you find relief soon