A man was shot in East Boston Sunday night, but when police arrived, he was not certain that he had been injured. Officers responded to a call about a person shot at the intersection of Saratoga and Marion streets at about 9 p.m., according to a Boston police spokesman, Officer James Kenneally. An 18-year-old man talking on a cellphone told the officers he believed he may have been shot in the back. Officers saw a bloodstain on his shirt and called emergency medical services, Kenneally said. The man, whose name was not released, was taken to Massachusetts General Hospital, where he was treated for injuries that were not life-threatening. He could not accurately describe the person who shot him, saying that the person ran up behind him.