I had RSI to the point I could not longer work, happily I am now pretty much back to full health. What really helped for me was:
Take a week off, no computing (actually I had no choice)
Physiotherapy for a month (once per week)
3M ergonomic mouse (it looks like a joystick)
Being conscious of my body position, when working its easy to get in to a tense position to ease the pain.
Stretching, having break to walk about
Exercise
Not using Apple keyboard or mouse, the Microsoft Ergo split keyboard is great, if only they did a small form version.
Switching to Vim text editor (no mouse).
Setting my Mac clock to speak the time every hour (so I know when to take a rest).
The book, "Its not carpal tunnel syndrome", it talks about identifying the root causes not just addressing the symptoms.
A herman miller chain, pretty expensive.
Work less, 9-5, no evening or weekend work.
