There are also some Angels who write down the deeds of human beings.
“But verily, over you (are appointed Angels in charge of mankind) to watch you, honorable, writing down (your deeds), they know all that you do” (Al-Infitar 82:10-12)
“Not a word does he (or she) utter, but there is a watcher by him ready (to record it)” (Qaf 50: 18)
One of the companions of Imam Ahmad, may Allah have mercy upon him, visited him while he was sick. He found him groaning from the sickness. He said:
“O Abu ‘Abdullah! Are you groaning? Tawus said ‘Indeed, the Angels write down everything, even the groan of a sick person, because Allah says:
Not a word does he (or she) utter, but there is a watcher by him ready (to record it(Qaf 50: 18)”‘
Therefore, Abu ‘Abdullah began to have (more) patience, and he stopped groaning, because everything is written down. “Not a word does he (or she) utter? – Meaning any word uttered by you is written. However, you might be rewarded or punished for it. This is based on the saying that was said.
 For what was reported by Salih bin Al-Imam Ahmad, he said: “During his sickness prior to death, my father said: ‘Take out the book of ‘Abdullah bin Idris.’ then said: ‘Read to me the narration of Laith that Tawus used to dislike groaning during sickness.’ After that I did not hear to my father a groan till he died.” Siyar A’lam An-Nubula (11:215).
Source : Al-’Aqidah Al-Wasitiyyah (2 Vol. Set) – Author: Muhammad bin Salih Al-’Uthaimin – Publisher: Darussalam Publishers & Distributors