Natural gas prices gave up some of its recent rebound as heavy stockpiles continue to keep a lid on any rally. Futures for March delivery settled down 4.2 cents, or 2%, at $2.098 a million British thermal units on the New York Mercantile Exchange. The retreat ends a two-session winning streak that had brought the largest back-to-back gains in a month, 8.5%, from traders anticipating higher demand for the heating fuel from a burst of…