The phrase "touched a nerve ending" is commonly used to describe something that has caused a strong emotional reaction. However, there are various synonyms that can be used to convey the same meaning. One alternative could be "struck a chord," which implies that something has resonated deeply with someone. Another similar phrase is "hit a nerve," which suggests that something has provoked a strong response. "Pushed someone's buttons" is another expression that can be used to describe when someone has been emotionally triggered. Ultimately, there are many ways to describe when something has touched a nerve ending, and using different phrasing can add variety and nuance to your writing.