Boil a large pot of salted water and cook rotini pasta according to package directions until al dente.

Drain the pasta and rinse under cold water until fully cooled.

In a large mixing bowl, whisk together the mayonnaise, sour cream, milk, ranch dressing mix, and black pepper.

Add the cooled pasta, crumbled bacon, peas, cubed cheddar, red onion, and cherry tomatoes to the dressing.

Toss all ingredients until the pasta is evenly coated.

Cover and refrigerate for at least 30 minutes before serving to allow flavors to meld.