An 11-year-old Encinitas boy was “doing very well” at Scripps Memorial Hospital-Encinitas Thursday after being shot at school by an unknown gunman, sheriff’s investigators said. The boy, whose name is being withheld, was playing on the soccer field at Park Dale Lane School Thursday morning when he “felt a sharp pain” in his chest and discovered a wound, a sheriff’s department spokesman said. He was transported to the hospital where, during surgery, a physician discovered a small-caliber bullet inside the wound. Late Thursday, the boy was in stable condition and “doing very well,” said Cindy Karlicek, nursing supervisor. She declined to describe the extent of the wound but noted that “it’s not minor--he had surgery.” The sheriff’s spokesman said, “It appears the boy was struck by a random shot fired from an unknown location.” Deputies interrogated area residents in hopes of finding clues, but none were forthcoming late Thursday.