bug up sb's butt

(have / get) a bug up your butt / ass
(be angry about something that is trivial or of little importance)

Do you have a bug up yous ass? (=(Why) are you angry?)
Well, he has a bug up his ass.

What crawled up your butt and died?
Do you have a bug up your ass?
What bug is up his butt?

Related vocabulary:
[какая муха тебя укусила]
What has gotten into you? (AmE)
[what has got into you?]

"Ass" is a bit dangerous, use "butt"