Impolite way to express something that annoying or nuisance.

If someone or something is being a pain in the ass it means that they're being annoying. For example, you're doing your homework but your friend keeps bothering you and won't leave you alone. You can say, "What a pain in the ass." You can also say, "What a pain in the neck." They mean the same thing.

it means something or someone that causes trouble; a source of unhappiness cowboy..

a "pain in one's ass" is an adjective phrase to pertain someone who causes trouble or just a source of unhapiness: one typical example is dating a girl who keeps telling her never-ending drama, or a young boy who always got a red mark in his class card, will be described as pain in the ass. :)

ass=asshole 　hips 肛門 尻 ...etc so you'd better not use the phrase in public. It is used for not only the phrase but also other phrases ... Kiss my ass! etc....(I don't like this phrase) pain in the ass If you are pain in the ass , you are menace just like 痔　haha