What are the conflicts in Siddhartha?
Certainly, there is the conflict between Siddhartha and his father when Siddhartha first decides that he wants to leave home and rejects the teachings that have not allowed him to reach nirvana.
There is the later conflict between Siddhartha and the Buddha, when Siddhartha takes issue with the Buddha's teachings and cannot stay and follow him. At the same time, he conflicts with Govinda, his best friend, who wants to stay and join the Buddha while Siddhartha wants to keep traveling.
Siddhartha's personality and behaviors conflict with what Kamaswami wants him to be like and do when he arrives in the city. He even, to a certain degree, conflicts with Kamala, both when she first rejects him and, later, when she falls in love with him though he does not love her.
Later, Siddhartha conflicts to a great extent with his son, after Kamala dies by the river where Siddhartha works as a ferryman, alongside Vasudeva. He conflicts with himself at this time as well because, although he wants to reach nirvana, he also holds on to his pain concerning his son, and holding onto his pain will prevent him from achieving enlightenment.