pain (in the neck) n.1
1. [late 19C+] a feeling of irritation; see give someone a pain in the neck
2. [1910s+] an annoying person, a bore, a euph. for pain in the arse n.
3. an annoying situation, anything considered unpleasant, typically a task one does not wish to perform.
4. (Aus.) a general insult.
[late 19C+] of a person, thing or situation, to irritate someone.