Boil salted water in a large pot, add elbow pasta, and cook for 7-9 minutes until al dente. Drain and rinse under cold water.

Transfer pasta to a mixing bowl, add half of the dill pickle juice, toss gently, let sit for 5 minutes, then drain excess juice.

In a separate bowl, mix mayonnaise, sour cream, remaining dill pickle juice, Sriracha, fresh dill, salt, and black pepper until smooth.

In a large bowl, combine flavored pasta, cheddar cheese, sliced dill pickles, and onion. Fold in the dressing until evenly coated.

Cover and refrigerate for 4-6 hours to enhance flavors before serving.