Heat an outdoor grill or grill pan over medium heat. Preheat the oven to 400 degrees F.
Carefully make a slit into the side of each pork chop using a chef's knife to create a pocket to stuff ingredients into. Mix together the feta, spinach, olives and sun-dried tomatoes in a medium bowl. Stuff each pork chop with the spinach mixture and rub each with 1/4 teaspoon salt and 1/4 teaspoon pepper. Secure each pork chop with a wooden skewer or toothpicks (remember to remove before serving).
Brush oil on the grill grate to prevent sticking. Grill the pork chops until nicely browned, 6 to 8 minutes, turning every few minutes to create grill marks. Transfer to a baking sheet and finish cooking in the oven until the pork reaches an internal temperature of 140 degrees F, 15 to 20 minutes.