Preheat the barbecue to medium-high. Arrange all ingredients, except chicken and pita, on a large platter, but leave room for them. Lightly oil the barbecue grill if prone to sticking. Grill the kebabs 3 to 4 minutes per side, or until cooked through. Heat the pita on the grill when the kebabs are almost done. Place the kebabs and pita on the platter and serve.