bitter pill vs misery

bitter pill

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

misery

noun
  • Great unhappiness; extreme pain of body or mind; wretchedness; distress; woe. 

  • A bodily ache or pain. 

  • poverty. 

  • Cause of misery; calamity; misfortune. 

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