1週4日目 かゆくてたまらない
Condition・emotion・limit
接続：Vて／Aくて／Naで＋ならない
just feel very; Uncontrollable natural emotions
注意 / Note：〜かなわない is mainly unpleasant due to external influences; 〜ならない is an emotion that arises spontaneously; 〜たまらない emphasizes the extreme level.
比較 / Compare：Same article: 〜てたまらない／〜てしかたがない／〜てしょうがない. These models are often mistakenly chosen for each other — carefully read the 接続 and nuances above and then decide.
よく出る形 / Common form：動て形／イ形くて／ナ形で＋ならない。Or go with 気・心配・残念・不思議. It's more about emotions naturally surging up, uncontrollably.
将来が心配でならない。
I keep worrying about the future.
なぜか故郷が懐かしくてならない。
I don't know why I miss my hometown so much.
あの時の判断が正しかったのか、今も気になってならない。
Whether the decision was right at that time, I still wonder.