pang of conscience vs repentance

pang of conscience

noun
  • A feeling of shame, guilt, or embarrassment, resulting from behavior which one regrets. 

repentance

noun
  • A feeling of regret or remorse for doing wrong or sinning. 

  • The condition of being penitent. 

How often have the words pang of conscience and repentance occurred in a corpus of books? (source: Google Ngram Viewer )