(idiomatic) To make a remark or perform a deed which produces a strong response, especially an emotional response such as anxiety or annoyance, because it calls to mind something which has been a source of concern or embarrassment.
Louis B. Seltzer, editor of the Cleveland Press, . . . banged out an editorial that raised uncomfortable questions about the state of the U.S. at a moment of world responsibility. His piece touched a nerve: in the following week, 1,000 people had tried to reach him by phone or written him letters or stopped him on the street to talk about it.
The austerity of my tone seemed to touch a nerve and kindle the fire that always slept in this vermilion-headed menace to the common weal, for she frowned a displeased frown and told me for heaven's sake to stop goggling like a dead halibut.
The president's supporters . . . are trying to exert greater control over universities, touching a nerve among an increasingly defiant student movement.