てかなわない

Expresses that a state is so intense, usually unpleasant or troublesome, that the speaker can hardly bear it: "unbearably ~" or "so ~ I can't stand it." It is mainly used to complain about situations that annoy or wear on the speaker.

A conversational way to complain about one's own discomfort or annoyance. It typically follows words for unpleasant states such as busyness, noise or heat. Unlike patterns that simply intensify a feeling, it carries a clear sense of being bothered or put out by the situation.

• てたまらないN2「てたまらない」is used freely with positive and negative feelings as well as physical sensations; it is the preferred choice for expressing positive emotions, and you can also say 「会いたくてたまらない」. Its register is neutral. When talking about something tiresome, the two are roughly interchangeable, but 「てかなわない」sounds more like a complaint.
• てしょうがないN3「てしょうがない」is neither positive- nor negative-leaning, and is often used for positive emotions like missing someone or being happy; it can also take the form 「たくて」to express desire. 「てかなわない」is mainly for complaining about unpleasant things. For negative feelings, the two are mostly interchangeable, but the latter carries a stronger whining tone.
• 〜てしかたがないN3「〜てしかたがない」emphasizes feelings or sensations so intense they cannot be controlled, and is also common for positive feelings like missing someone or being happy; its register is neutral. 「てかなわない」mainly complains about burdens and is more colloquial. When expressing discomfort such as sleepiness or heat, the two are mostly interchangeable.
• てならないN2「てならない」leans written and is used only for the spontaneous arising of emotions, sensations, or thoughts, often attaching to 「思われる」「気がする」. 「てかなわない」is colloquial, usually carries a complaining nuance, and can also describe external situations like noise or weather being unbearable.
• にたえる / にたえないN1「にたえる／にたえない」is written language, attaching to words like 「見る」「鑑賞」to indicate whether something can withstand evaluation, or to words like 「感謝」in formal expressions of gratitude. 「てかなわない」is colloquial and mostly complains about one's own inability to cope; the two cannot be interchanged.

てたまらない, てしょうがない and 〜てしかたがない also express an intense feeling and are commonly used for positive feelings such as joy, while てかなわない is mainly used for unpleasant situations and stresses the speaker's annoyance. てならない is typically used for feelings that well up on their own, and にたえる / にたえない attach differently: にたえる means something is worth or able to withstand an action, and にたえない means something is too painful to watch or listen to, or expresses deep emotion.