A short time before, someone asked me if the martyrs felt pain in their so many tortures. He said that God gave them patience and they endured so many tortures.
And I told him: Man, as a man [alone], cannot bear even the first pain that he comes across. Physiologically, he should faint immediately. But their nous and heart were fixated on Christ: "Lord Jesus Christ, have mercy on me," not "take away my pain". [Christ] knows the pain and allows it as much as is needed to heal your soul.
He gave you a canon instead of other canons. You should not say "take it back". God knows your pain. A pill or a cup of coffee aren't necessary. Cut them out. Of course, man has the right to say to God in his life: "My God, take away my pain". But I think that it is better to take up his pain. Perhaps I am wrong, but I love this error.
Do not ask that your canon be lessened. (In reality, I had the thought in those days to ask to do fewer prostrations, because I was tiring from the three hundred.) Struggle with whatever God has given you.
(amateur translation of text from source)