reward against pain and tiredness, sorrow and difficulty.

(1) whatever a muslim faces by way of pain, tiredness, worry, anxiety or trouble-even if it be a thorn that pricks him once,
allah surely recompenses him by turning that as an expiation of his sins. {bukhari and muslim}.
(2) it is very peculiar with a believer. surely everything with him is commendable and no one else besides him has a share in it. if he is happy, he thanks and
that is better for him. and if he suffers difficulty, he endures patiently and this (too) is better for him.{muslim). ref..the pearls of hadith. darul ishaat