Cook the rotini pasta according to package instructions in a large pot of salted boiling water until al dente. Drain and rinse under cold water to cool completely.

While the pasta cooks, prepare the bacon. In a skillet over medium heat, cook the bacon until crispy, about 8-10 minutes. Transfer to a paper towel-lined plate to drain, then crumble into small pieces.

In a small bowl, whisk together mayonnaise, sour cream, ranch seasoning mix, lemon juice, garlic powder, and black pepper until smooth. Set aside.

In a large mixing bowl, combine the cooled pasta, crumbled bacon, cherry tomatoes, cucumber, red onion, and shredded cheddar cheese.

Pour the ranch dressing over the pasta mixture and toss gently until everything is evenly coated.

Cover and refrigerate for at least 30 minutes to allow the flavors to meld. Serve chilled.