What is the nature of the questions intended in verse 101 of Surat Al-Ma'idah, and does every question from whose answer hardship upon the soul is expected fall under this category?

The questions prohibited in the verse (O you who have believed, do not ask about things which, if made manifest to you, would trouble you) are those that are useless and may harm the questioner, such as questions asked in mockery or out of obstinacy, or those whose answers might displease or burden the questioner.

As for asking people of knowledge about what is beneficial in matters of religion and worldly life, it is permissible, indeed, it is commanded, as in the verse (So ask the people of the message if you do not know) and the saying of the Prophet, peace and blessings be upon him: "Indeed, the cure for inability is to ask."

The prohibition of excessive questioning is also mentioned in the Sunnah as something disliked, as in the hadith of Mughira ibn Shu'ba: "Indeed, Allah has disliked for you... excessive questioning."