Cook pasta according to package directions; drain.
Meanwhile, toss shrimp with the Cajun seasoning, and salt and pepper, to taste.
Heat olive oil in a large skillet over medium-high heat. Add shrimp and sauté until pink, 4-5 minutes. Transfer to a plate and keep warm.
Add garlic to skillet and cook until fragrant, 1-2 minutes. Stir in 1/4 cup chicken broth and scrape up any brown bits from the bottom of the pan.
Stir in heavy cream and Parmesan cheese. Simmer until sauce is slightly thickened, 3-5 minutes. Add additional broth, if desired, until sauce reaches desired consistency. Stir in the cooked pasta, shrimp, tomatoes, parsley and lemon juice.
Season with additional salt and pepper, to taste. Garnish with additional grated Parmesan, if desired.