anyone have anxiety after injury, in particular whiplash?

My sister was rear-ended a few weeks ago.  It is her third time with damage to her car.  I know, we joke her car is invisible.  So there may have been some existing damage from other incidents however the symptoms are much more noticable this time over the previous ones.  She is normally in great health and her anxiety is that there is something more serious wrong with her (she jumps to thoughts of cancer) becasue she is not understadning her pain I guess.  Anyone else have something like this?  I just keep telling her that she is not used to feeling pain, since she is normally so healthy, that she is not accustomed to these feelings.  Any other suggestions?