expression, i-adjective
headache-inducing; vexing; troublesome
Describes a problem or situation that causes worry or frustration, as if giving one a headache. Often used attributively before nouns like 問題 (problem).
See also: 頭が痛い
それは頭の痛い問題だ。
That's a vexing problem.
頭の
It's a headache-inducing situation, but we don't have enough budget.
Literally means 'my head hurts' (physical pain) or figuratively 'I'm worried/troubled'. 頭の痛い is an attributive form modifying a noun, while 頭が痛い is a predicate phrase.
A fixed expression combining 頭 (head) + の (possessive particle) + 痛い (painful). The figurative meaning derives from the idea that a troublesome matter causes a headache.