Preheat oven to 350°.
Trim the chicken of any fat.
Place in a baking pan and drizzle with the melted butter.
Season with garlic, pepper and salt.
Bake for about 40 minutes, until cooked through.
Refrigerate until cool and then cut into chunks.
In a serving bowl, combine the chicken, cooked pasta, celery, onion and grapes.
In a separate bowl, combine the curry powder with the mayonnaise and mix well.
Add to the pasta mixture and stir to combine.
Chill for several hours or overnight before serving.
Add extra salt and pepper if desired before serving.