touch a sore spot

touch (on) a sore spot

To evoke a strong and negative emotional reaction in someone; to do or say something that upsets someone in a deeply personal way. Your column must have touched a sore spot with readers, because we are getting slammed with negative feedback. I could tell he was touching on a sore spot, because Jane went deathly silent when he brought up her former employer.
See also: sore, spot, touch
Farlex Dictionary of Idioms.

touch a sore spot

 and touch a sore point
Fig. to refer to a sensitive matter that will upset someone. (Fig. on the notion of touching an injury and causing pain.) I seem to have touched a sore spot. I'm sorry. I didn't mean to upset you. When you talk to him, avoid talking about money. It's best not to touch a sore point if possible.
See also: sore, spot, touch
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • accompany (one) on a/(one's) journey
  • accompany on a journey
  • be (not) a patch on
  • be out of (one's) league
  • be out of somebody's league
  • be/have done with somebody/something
  • bargain
  • bargain for (someone or something) with (someone)
  • brief (someone) about (someone or something)
  • brief about