Why is it difficult for Shane to visit San Francisco in the novel, The Other Boy?

Shane closely associates San Francisco with his past, specifically his early transition from female to male. Though his classmates in San Francisco supported Shane, his identity as a transgender male within the Creative Academy school distanced Shane from his peers. Shane is further reminded of his birth gender whenever he visits San Francisco because Adam struggles to accept that Shane identifies as a boy. This reluctance for Adam to part with the little girl he adored triggers feelings of betrayal and frustration for Shane that he rarely experiences in Los Angeles.