Prosecutors in a pretrial hearing yesterday played a taped confession from Natavia Lowery, accused of killing real estate agent Linda Stein. Stein, a Prudential Douglas Elliman broker, was killed in her apartment on October 30, 2007. On the tape, Lowery said she “wasn’t herself” when she hit Stein repeatedly in the head with a yoga stick. But Lowery’s attorney said her confession was coerced and she was questioned without a lawyer present. Lowery pleaded not guilty to second-degree murder. Defense attorneys claimed blood evidence showed the killer was a man.