It would be a tie between pain and denial.
Pain is temporary, denial is longer lasting- but possibly never ending. Denial can be so very frustrating and lead to a different type of pain.

Tickle torture, because being tickled turns me on ;)

Orgasm denial would definitely come first (lul that pun). One of my biggest kinks, I love being horny, edging to oblivion, and still not being able to cum.
Pain would probably come second. I don't like extreme pain, hard cbt and so on, but moderate amount of pain, spanking, whipping, nipple clamps etc. are also really arousing.
I'm very ticklish and hate being tickled, so that would definitely come last.