royal pain

noun2

1. •
   (slang) Someone or something that is very annoying.

   • And while the spine's no doubt a miraculous array of vertebrae, ligaments, muscle and nerve tissue, it can also be a royal pain in the... well, lower back region. — 1992
2. •
   (slang) A feeling of being very annoyed.

   • He gave out a big yawn while he said that. Which is something that gives me a royal pain in the ass. — 1951