What are the tensions in Winston’s life in 1984?
To me, the major tension in his life is between what he wants to be, on the one hand, and what he has to be in order to stay alive, on the other.
Winston wants desperately to be an individual. He wants to have his own thoughts and his own memories. But he lives in a society where such things are impossible (or at least completely forbidden). This causes the central tension in his life.
I suppose you could say that another tension is between his desire to rebel and his understanding that rebellion is futile. He knows from the beginning that he's doomed, but he can't help himself and keeps rebelling.