The word(s) "painful" appears 72 time(s) in 72 verse(s) in Quran in Muhammad Habib Shakir translation.

(11) And whoever kills a believer intentionally, his punishment is hell; he shall abide in it, and Allah will send His wrath on him and curse him and prepare for him a painful chastisement.

(12) Announce to the hypocrites that they shall have a painful chastisement:

(13) And their taking usury though indeed they were forbidden it and their devouring the property of people falsely, and We have prepared for the unbelievers from among them a painful chastisement.

(14) Then as for those who believe and do good, He will pay them fully their rewards and give them more out of His grace; and as for those who disdain and are proud, He will chastise them with a painful chastisement. And they shall not find for themselves besides Allah a guardian or a helper

(15) Surely (as for) those who disbelieve, even if they had what is in the earth, all of it, and the like of it with it, that they might ransom themselves with it from the punishment of the day of resurrection, it shall not be accepted from them, and they shall have a painful punishment.

(16) Certainly they disbelieve who say: Surely Allah is the third (person) of the three; and there is no god but the one Allah, and if they desist not from what they say, a painful chastisement shall befall those among them who disbelieve.

(17) O you who believe! Allah will certainly try you in respect of some game which your hands and your lances can reach, that Allah might know who fears Him in secret; but whoever exceeds the limit after this, he shall have a painful punishment.

(18) And leave those who have taken their religion for a play and an idle sport, and whom this world's life has deceived, and remind (them) thereby lest a soul should be given up to destruction for what it has earned; it shall not have besides Allah any guardian nor an intercessor, and if it should seek to give every compensation, it shall not be accepted from it; these are they who shall be given up to destruction for what they earned; they shall have a drink of boiling water and a painful chastisement because they disbelieved.

(19) And to Samood (We sent) their brother Salih. He said: O my people! serve Allah, you have no god other than Him; clear proof indeed has come to you from your Lord; this is (as) Allah's she-camel for you-- a sign, therefore leave her alone to pasture on Allah's earth, and do not touch her with any harm, otherwise painful chastisement will overtake you.

(20) And when they said: O Allah! if this is the truth from Thee, then rain upon us stones from heaven or inflict on us a painful punishment.