Place chicken breasts, balsamic vinegar, olive oil, garlic, honey, salt and pepper in a large resealable plastic bag. Refrigerate for 4 hours to overnight.

Meanwhile cook pasta according to package directions. While the pasta is cooking combine the pineapple, grapes, celery, onions, mayonnaise, sour cream and season salt in a large bowl, set aside. Drain and rinse the pasta with cold water to stop the cooking process. Add to the bowl with the grapes and vegetables and gently stir to combine. Cover and refrigerate until ready to add the chicken.

Preheat grill to medium/medium-high heat. Remove chicken from marinade and place on preheated grill. Cover and grill for 20 minutes turning half way through cooking time. Chicken is done when the juice of the chicken is no longer pink. Let chicken rest for 5 minutes then slice or dice and toss with pasta salad. Refrigerate any leftovers.