A firefighter was hospitalized for chest pain he experienced at the scene of a two-alarm blaze on Beacon Hill Saturday night, the Boston Fire Department said. The unidentified firefighter was admitted overnight to Massachusetts General Hospital, department spokesman Steve MacDonald said. No information was available on his condition. The fire began about 10 p.m. in a four-story brick building at 119 Charles St., the department said. It caused an estimated $1 million in damage and displaced five people, MacDonald said. It took firefighters about an hour to extinguish the blaze, officials said, and the cause was under investigation. The building is home to Boston Antiques Company, located in the basement, with housing units on upper floors.