" “‘I will not,’ he answered, but later he changed his mind and went.
“Then the father went to the other son and said the same thing. He answered, ‘I will, sir,’ but he did not go.
“Which of the two did what his father wanted?”
“The first,” they answered."
You can take all the time you need to tell God how much you don't want to do something. God understands, for the heart of man is desperately wicked (Jer 17:9).
In the end, it does not matter if you want to do something or not, only that it gets done. And it should be no surprise to us that God will call us to do things we do not want to do! In the words of Dietrich Bonhoeffer "When Christ calls a man, he bids him come and die." If you are called to be like Christ, you are called to a life of self-denial and obedience like Christ. These things are hard!
But the thing is, Jesus understands what he's asking you to do, and he asks you to do them anyway. He knows full well what you can endure and what you can accomplish if you put your trust in him. He knows you don't want to do them, and yet he still asks. And so the only question that remains is do you have the faith to follow Christ, even to the cross? If not, pray for faith, otherwise for strength and endurance.