Heat the olive oil in a skillet over medium heat, and add onion, garlic and pork chops. Cook until pork chops are browned. Add chicken broth, soy sauce and vinegar to the skillet, and bring to a boil. Put a lid on the skillet, and simmer 20 to 25 minutes. Remove chops from the skillet. Reserve broth in skillet. Add the brown sugar, cornstarch and pineapple to skillet with the broth mixture. Bring to a boil. Serve over cooked pork chops and with white rice.