A state of affairs, action, or belief which is an enduring basis for disagreement or dissatisfaction.(noun)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "sore point" in a sentence
"Letters from the cousin, Mrs. Sotheran, show, however, that William Godwin's novel-writing was likewise a sore point in his family."
"She was friends with GF's wife, primarily because we had children the same age, but GF himself was a sore point with her, and I didn't want to go into it then and there."
"It was also a sore point that his last mission had been the flight prior toChallenger, so he had the additional plum of having back-to-back missions."