bitter pill vs torture

bitter pill

noun
  • Used other than figuratively or idiomatically: see bitter, pill. 

torture

noun
  • The intentional causing of somebody's experiencing agony. 

  • The "suffering of the heart" imposed by one on another, as in personal relationships. 

  • (often as "absolute torture") Stage fright; severe embarrassment. 

verb
  • To intentionally inflict severe pain or suffering on (someone). 

How often have the words bitter pill and torture occurred in a corpus of books? (source: Google Ngram Viewer )