Is each and every Hadith recorded in Sahih Bukhari considered as words of the Prophet Muhammad (Sallallahu Alaihi wa Sallam)? I ask because there are different Ahadith about the revelation of the first few verses of Surah At-Tahreem. Some Ahadith say that Hazrat Hafsah (Radiya Allahu Anha) served Prophet Muhammad (Sallallahu Alaihi wa Sallam) the honey while others say it was Hazrat Zainab (Radiya Allahu Anha). Some traditions say that it was because of the jealousy of the wives that the Prophet Muhammad (Sallallahu Alaihi wa Sallam) stayed away from them for a month while another Hadith says that it was because the Prophet (Sallallahu Alaihi wa Sallam) had sprained his foot. Please explain.

Praise be to Allah, the Lord of the World; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

There is a unanimous agreement among Muslim scholars that Sahih al-Bukhari and Sahih Muslim are the most correct books after the Holy Qur'an. The whole Muslim Ummah accepts such a truth with explicit conviction.
Imam al-Nawawi records such an agreement in his explanation of Sahih Muslim.
Hafiz Abu Nasr al-Sijizi , while demonstrating the authenticity of Sahih al-Bukhar, said: 'There is agreement among Fuqaha and other scholars of Islam that if one says: 'I swear by Allah that my wife is divorced if the whole Hadith of Sahih al-Bukhar is not sound and that its words are not those of Allah's Messenger (Sallallahu Alaihi wa Sallam)', there will be no violation of an oath' .
Such authenticity is gained because of accurate and strict conditions that al-Bukhari (may Allah's Mercy be upon him) stipulated while collecting the Hadith.
Thus, we state that the words of the Hadith of Sahih al-Bukhari are those of Allah's Messenger (Sallallahu Alaihi wa Sallam).
As for the multiple narrations concerning the reason of the revelation of the first verses of al-Tahreem Surah, this is because of multiple occurrences of the story.
Imam Ibn Kathir , after relating many narrations in this concern, said: 'It might be said that there are two incidents, and this is feasible. But, it is not certain that these two incidents are behind the revelation of the above-indicated verses' .
al-Hafiz Ibn Hajar said in his book al-Fat-h: 'To bring different opinions together, we believe in multiple narration, since nothing prevents the existence of several reasons for an incident' .
As for the Prophet's (Sallallahu Alaihi wa Sallam) motive behind taking an oath of desertion of his wives for one month, we think it is also a matter of multiple narrations.
Allah knows best.