てしょうがない / てしかたがない

てしょうがない and てしかたがない say a feeling is so strong you can't do anything about it: "unbearably ~", "I can't stop ~", "dying to ~". They follow the て-form: an い-adjective takes くて, a な-adjective で, and a verb of feeling its own て-form.

The last one is the commonest verb case: たい changes to たくて like any い-adjective.

• × 眠いでしょうがない → 眠くてしょうがない

It takes feelings and sensations that come over you – worry, loneliness, sleepiness, pain, wanting something – and not a deliberate action. The feeling is the speaker's own; for someone else's, add ようだ or らしい.

しょうがない and しかたがない

The two mean the same. しょうがない, a contraction of しようがない, is what you say in conversation. しかたがない, often written しかたがない仕方がない, is a little more neutral and is the one for writing; in speech it drops が, しかたない. The polite forms are しょうがありません and しかたがありません.

てしょうがない or てもしょうがない

With も the meaning changes. てもしょうがない is "there's no point ~ing": the action is useless, not the feeling strong.

てたまらない and てならない

てたまらない means the same, and most sentences take either. てしょうがない is the more casual of the two; てたまらない is the usual choice for heat, cold, pain and hunger. てならない is the written counterpart, and it seldom takes physical sensations at all.