The word(s) "painful" appears 75 time(s) in 75 verse(s) in Quran in Mohsin Khan translation.

(11) Give to the hypocrites the tidings that there is for them a painful torment.

(12) And their taking of Riba (usury) though they were forbidden from taking it and their devouring of men's substance wrongfully (bribery). And We have prepared for the disbelievers among them a painful torment.

(13) So, as for those who believed (in the Oneness of Allah - Islamic Monotheism) and did deeds of righteousness, He will give them their (due) rewards - and more out of His Bounty. But as for those who refused His worship and were proud, He will punish them with a painful torment. And they will not find for themselves besides Allah any protector or helper.

(14) Verily, those who disbelieve, if they had all that is in the earth, and as much again therewith to ransom themselves thereby from the torment on the Day of Resurrection, it would never be accepted of them, and theirs would be a painful torment.

(15) Surely, disbelievers are those who said: "Allah is the third of the three (in a Trinity)." But there is no Ilah (god) (none who has the right to be worshipped) but One Ilah (God -Allah). And if they cease not from what they say, verily, a painful torment will befall on the disbelievers among them.

(16) O you who believe! Allah will certainly make a trial of you with something in (the matter of) the game that is well within the reach of your hands and your lances, that Allah may test him who fears Him unseen. Then whoever transgresses thereafter, for him there is a painful torment.

(17) And leave alone those who take their religion as play and amusement, and whom the life of this world has deceived. But remind (them) with it (the Qur'an) lest a person be given up to destruction for that which he has earned, when he will find for himself no protector or intercessor besides Allah, and even if he offers every ransom, it will not be accepted from him. Such are they who are given up to destruction because of that which they have earned. For them will be a drink of boiling water and a painful torment because they used to disbelieve.

(18) And to Thamud (people, We sent) their brother Salih. He said: "O my people! Worship Allah! You have no other Ilah (God) but Him. (La ilaha illallah: none has the right to be worshipped but Allah). Indeed there has come to you a clear sign (the miracle of the coming out of a huge she-camel from the midst of a rock) from your Lord. This she-camel of Allah is a sign unto you; so you leave her to graze in Allah's earth, and touch her not with harm, lest a painful torment should seize you.

(19) And (remember) when they said: "O Allah! If this (the Qur'an) is indeed the truth (revealed) from You, then rain down stones on us from the sky or bring on us a painful torment."

(20) And a declaration from Allah and His Messenger to mankind on the greatest day (the 10th of Dhul-Hijjah - the 12th month of Islamic calendar) that Allah is free from (all) obligations to the Mushrikun (See V.2:105) and so is His Messenger. So if you (Mushrikun ) repent, it is better for you, but if you turn away, then know that you cannot escape (from the Punishment of) Allah. And give tidings (O Muhammad صلى الله عليه وسلم) of a painful torment to those who disbelieve.