Pain erases Sins Hadith

Volume 7, Book 70, Number 544:

Narrated 'Aisha:

(the wife of the Prophet) Allah's Apostle said, "No calamity befalls a Muslim but that Allah expiates some of his sins because of it, even though it were the prick he receives from a thorn."

Volume 7, Book 70, Number 545:
Narrated Abu Sa'id Al-Khudri and Abu Huraira:

The Prophet said, "No fatigue, nor disease, nor sorrow, nor sadness, nor hurt, nor distress befalls a Muslim, even if it were the prick he receives from a thorn, but that Allah expiates some of his sins for that."