Monday at work I was taking the copy paper from the box and putting it away on the shelf, when my back decided it didn't like what I was doing. It's been stiff and sore since then. That's happened a few times before, so I'm hoping it's just a strain.
This kind of aggravation reminds me of when a character gets hurt in a book or movie. Sometimes it's almost miraculous how that person can heal so instantly, run around and do all sorts of heroic actions. In real life, it's not usually the case.
Remember, if you include an injury in the plot, give your character time to suffer instead of making everything all right real fast. And if the hero or heroine has to ignore the pain to reach a goal, at least include some references to the fact it's there, like sweat on the brow, bruises, gouges, swellings or some other kind of evidence that all is not perfect.
Rising above difficulties is always a good way to heighten tension in a story, so don't make everything seem too easy. Pain is part of the human condition, unfortunately, so think about including it in when you write.