In a large bowl, combine chicken, celery, mushrooms, red or green pepper (if you like), pecans, and bacon.
In a medium bowl, stir together sour cream, mayonnaise, and lemon juice. Add to chicken mixture; toss to coat. Season to taste with salt and pepper. Cover; chill for 2 to 24 hours.
Serve in lettuce-lined pita or on salad plates. Makes 6 to 8 servings.