Permissibility of expressing feelings of agony in Serious Illness

Imam Al-Nawawi’s Riyad-us-Saliheen
Chapter 149
Permissibility of expressing feelings of agony in Serious Illness

914. Ibn Mas`ud (May Allah be pleased with him) reported: I visited the Prophet ({PBUH) while he was suffering. I said: “(O Messenger of Allah!) You suffer too much.’ He said, “Yes, I suffer as much as two men of you.”
[Al-Bukhari and Muslim].

915. Sa`d bin Abu Waqqas (May Allah be pleased with him) reported: The Messenger of Allah (sallallaahu ’alayhi wa sallam) came to visit me when I had a severe pain. I said: “I am suffering from such trouble as you are observing. I am a wealthy man and the only heir of mine is my daughter.” (Then Sa`d narrated the whole incident).
[Al-Bukhari and Muslim].

916. Al-Qasim bin Muhammad reported `Aishah (May Allah be pleased with her) said: “Oh, my head.” (It was hurting due to pain.) Thereupon the Prophet (sallallaahu ’alayhi wa sallam) said, “Rather it is I who says: `Oh, my headache.”’ (Then Al-Qasim narrated the complete narration).
[Al-Bukhari].