George Orwell wrote that "Writing a book is a horrible, exhausting, struggle, like a long bout of some painful illness" (in 'Why I Write), do you agree?
Yes, I agree, that’s a George Orwell quote all right.*
“All writers are vain, selfish, and lazy, and at the very bottom of their motives there lies a mystery. Writing a book is a horrible, exhausting struggle, like a long bout of some painful illness. One would never undertake such a thing if one were not driven on by some demon whom one can neither resist nor understand.”
You can find out what Orwell felt were the four motives (the irresistable demons that drove writers) at https://www.brainpickings.org/2012/06/25/george-orwell-why-i-write/.
*Do I agree with Orwell? Not really. Generalisations like that tend to be incomplete and unsatisfactory ways of describing the world.)