Fire up your Pit Boss grill to 400°F. If using a gas or charcoal grill, set the temp to medium heat. In a bowl, combine the chicken broth, mustard, apple cider vinegar, and 1 tablespoon of Pit Boss Homestyle Pork Rub. Whisk well to combine and set aside.
Generously season the pork shoulder with the remaining 3 tablespoons of Homestyle Pork Rub on all sides of the pork shoulder, then place on the grill and sear on all sides until golden brown, about 10 minutes.
Remove the pork shoulder from the grill and place in the disposable aluminum pan. Pour the chicken broth mixture over the pork shoulder. It should come about 1/3 to ½ way up the side of the pork shoulder. Cover the top of the pan tightly with aluminum foil.
Reduce the temperature of your Pit Boss grill to 250°F. Place the foil pan on the grill and grill for four to five hours, or until the pork is tender and falling off the bone.
Remove the pork from the grill and allow to cool slightly. Place on a cutting board and shred with meat claws, reserving about 2.5 cups. Fire up Pit Boss grill to 425°F.
In a mixing bowl, combine sour cream, BBQ sauce, and chili powder. Stir in cheddar cheese and pork until well combined.
Lay each tortilla flat on your work surface and scoop about ¼ cup of pork mixture in the center, lengthwise. Roll up tightly and place seam side down on baking sheet. Repeat with all tortillas, then brush tops lightly with olive oil.
Transfer baking sheet to grill and cook for 15-20 minutes at 400°F , or until cheese has melted and tortilla edges have turned a golden brown. Serve with extra BBQ sauce for dipping.