Begin by bringing a large pot of salted water to a boil over high heat. Add pasta and cook according to package instructions until al dente, usually about 8-10 minutes. Drain in a colander and rinse under cold water until cool.

In a large mixing bowl, whisk together the mayonnaise, sour cream, fresh lemon juice, Dijon mustard, garlic powder, salt, and pepper until smooth and creamy.

Add the cooked shrimp, finely chopped celery, red onion, thawed peas, and chopped dill to the bowl. Gently fold together with a spatula, ensuring each piece is well coated.

Gently fold the al dente pasta into the salad until fully coated with dressing.

Transfer to an airtight container or cover with plastic wrap. Refrigerate for at least 30 minutes to allow the flavors to meld.

Before serving, give the salad a gentle stir to redistribute the dressing and garnish with fresh lemon wedges.