it means 颈部扭伤or鞭抽式损伤.

由于头部突然的撞击而引起颈椎的受伤，向前方或者后方（撞击）都有可能 in chinese says people "挥鞭样损伤"

whiplash whip·lash / `wɪp,læʃ, `hwɪp,læʃ / noun 1 [uncount] a serious injury affecting your neck, caused when the vehicle you are in is hit from behind by another vehicle, which makes your head move violently 这个解释是：(车从后方被撞而引起的)颈部扭伤 2 [count] a hit from a whip 这个解释是：鞭打 WOOF

It's means "扭伤（niu shang）" maybe you can think it "pain" . I think so.

Whiplash injury to neck 急性颈扭伤,颈加速伸展性损伤 A cushion attached to the top of the back of an automobile's seat helps to prevent whiplash. 附在汽车座位后背顶端的垫子可用来防止脖子扭伤。 I hope that it can be of help to you.