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

(21) And an announcement from Allah and His Apostle to the people on the day of the greater pilgrimage that Allah and His Apostle are free from liability to the idolaters; therefore if you repent, it will be better for you, and if you turn back, then know that you will not weaken Allah; and announce painful punishment to those who disbelieve.

(22) O you who believe! most surely many of the doctors of law and the monks eat away the property of men falsely, and turn (them) from Allah's way; and (as for) those who hoard up gold and silver and do not spend it in Allah's way, announce to them a painful chastisement,

(23) If you do not go forth, He will chastise you with a painful chastisement and bring in your place a people other than you, and you will do Him no harm; and Allah has power over all things.

(24) And there are some of them who molest the Prophet and say: He is one who believes every thing that he hears; say: A hearer of good for you (who) believes in Allah and believes the faithful and a mercy for those of you who believe; and (as for) those who molest the Apostle of Allah, they shall have a painful punishment.

(25) They swear by Allah that they did not speak, and certainly they did speak, the word of unbelief, and disbelieved after their Islam, and they had determined upon what they have not been able to effect, and they did not find fault except because Allah and His Apostle enriched them out of His grace; therefore if they repent, it will be good for them; and if they turn back, Allah will chastise them with a painful chastisement in this world and the hereafter, and they shall not have in the land any guardian or a helper.

(26) They who taunt those of the faithful who give their alms freely, and those who give to the extent of their earnings and scoff at them; Allah will pay them back their scoffing, and they shall have a painful chastisement.

(27) And the defaulters from among the dwellers of the desert came that permission may be given to them and they sat (at home) who lied to Allah and His Apostle; a painful chastisement shall afflict those of them who disbelieved.

(28) To Him is your return, of all (of you); the promise of Allah (made) in truth; surely He begins the creation in the first instance, then He reproduces it, that He may with justice recompense those who believe and do good; and (as for) those who disbelieve, they shall have a drink of hot water and painful punishment because they disbelieved.

(29) And Musa said: Our Lord! surely Thou hast given to Firon and his chiefs finery and riches in this world's life, to this end, our Lord, that they lead (people) astray from Thy way: Our Lord! destroy their riches and harden their hearts so that they believe not until they see the painful punishment.

(30) Though every sign should come to them, until they witness the painful chastisement.