If you're in excruciating pain, you would probably be shoving people away just because you're in such bad pain. If you are ever in extreme pain, you usually aren't thinking clearly. Ever see videos on TV of when someone crashes their car or something, and then they have a broken neck but they keep trying to get up anyway? Same concept.
If you had back pain, you'd be getting into a stance where you feel the least pain... Then somebody comes along and tries to push you away, changing your stance... Wouldn't you push this person away as well?