Ponyboy is the best character to use for a specific man vs. self internal conflict. Ponyboy is much more introspective than the other Greasers. For that reason, he is the one Greaser that begins to consider the Socs as people with problems too. Granted, Ponyboy gets a little help from Cherry in this realization when she tells him "Things are rough all over."
Ponyboy's internal conflict is whether or not to carry on with the Greaser life. Deep down Ponyboy wants out of the Greaser life. He wants to continue his education and work toward improving himself and others. He sees the Greasers as brothers, but ultimately, Ponyboy knows that being a Greaser means continued violence and poverty. Ponyboy struggles with staying true to his brothers and doing what he knows he has to do to improve his own lot in life.