Our bodies tell a story of what we do all day long, everybody tells a different story because we are what we repeatedly do and repetitive strain injuries are a product of that repetition; they develop over time well after bad postural habits are formed. Sometimes these habits are so seemingly small and insignificant that we don't even realise strain patterns are forming, until perhaps someone like myself starts finding tender points in places you didn't know were sore.
RSI injuries take time to heal and it is important to remember that time does heal all wounds, however we are all impatient and no one likes to be in pain. The good news about RSI injuries taking a long time to develop means that there are plenty of opportunities along the way to do something about it before it becomes problematic. Remember prevention is best.