A 15-year-old boy was seriously injured in a shooting Friday afternoon in Hamlin Park on the North Side.The teen was in the park in the 3000 block of North Hoyne Avenue when two armed suspects approached him and at least one of them shot at him around 2:20 p.m., Chicago police said. The teen was struck in the back and was taken in serious condition to Lurie Children's Hospital, police said. The suspects fled the scene, and no arrests were made.