Why does the committed person feel like cursing the Divine Self and religion when performing good deeds?

These whisperings do not affect your faith, and you should not succumb to them. Strive to repel them. Your dislike and aversion to them are signs of the sincerity of your faith, and your struggle against them will be rewarded. Continue to disregard them and pay them no mind. Whenever any of them occur to you, say "I believe in Allah" and then cease thinking about it. Continue to supplicate to Allah to remove them from you.