CHICAGO — A man and a 16-year-old boy have been charged with murder in connection with the fatal shooting of 8-year-old Melissa Ortega, who was shot in the head as she walked through Chicago’s Little Village neighborhood with her mother this past weekend, Chicago police Superintendent David Brown announced. “We have found the offenders responsible for taking Melissa’s life and they have been charged,’’ Brown said during an afternoon news conference Wednesday afternoon at police headquarters. “Our city has been shaken, and no one can make sense of this tragedy,” Brown said. The boy, who Brown d…