Preheat grill to medium heat and place wooden skewers in water to soak.
Lay out the shrimp and pineapple on a cutting board. Thread the pineapple and shrimp on the skewers.
In a large bowl, mix the soy sauce, balsamic vinegar, honey, ginger, garlic, and pepper.
Add the skewers into the bag, careful not to puncture the bag. Pour the marinade around the pineapple and shrimp, making sure to coat each piece.
Set a timer for 10 minutes and allow the bag to marinate in the fridge. Don't leave it longer because the shrimp can start to break down.
Remove the kabobs from the bag and grill for 5-8 minutes or until the shrimp start to curl and turn pink. Flip once. Do not overcook!