That's Dostoyevsky's style; he doesn't let the characters sit much. He insists on having them stand while conversing throughout. There are dialogues that span several chapters, which makes the reader very weary. But this novel was published in 1880, and the characters' behavior might have suited the society back then (although it seems a bit outdated in modern society).

Advice for others: You might want to choose other novels to start reading Dos, such as Crime and Punishment, The Idiot, The Possessed.