Cook the elbow macaroni in salted water, per package instructions, drain and set aside to cool.
Chop the onion and celery. Cube the chicken. Chop or hand shred the parsley.
Mix the mayonnaise, dill pickle relish, lemon juice if using, onion, celery parsley, salt, and pepper. Taste and adjust seasoning if necessary.
Add the cubed chicken, shredded cheddar cheese, and cooked macaroni. Stir well and adjust salt and pepper again if necessary. Add more mayo if you desire.
Cover, and place in the refrigerator for at least 30 minutes for best flavor.
