Stir together the garlic and mayonnaise in a small bowl; set aside. Heat the butter in a skillet over medium-high heat. Cook and stir the chicken in the hot butter until white on the outside. Sprinkle with garam masala, and continue cooking until lightly browned on the outside and no longer pink in the center, about 4 minutes.
Spread the pita rounds with the garlic mayonnaise. Divide the chicken among the pitas, and place a pickle spear into each. Fold and serve.