Prepare pasta al dente per the directions on the box.
Drain the rotini, and then set aside.
Place a pan over medium heat and add a little oil.
While stirring occasionally, cook the zucchini, bell peppers, and onion for 8 minutes.
Add the tomatoes, season with salt, and cook for a few more minutes, or until the vegetables are tender.
Add the spinach and cook until wilted.
Melt the butter in a separate pot.
Add the flour and gently whisk to create a smooth paste.
Pour in the milk and whisk again.
Whisk in the remaining sauce ingredients and simmer for about 5 minutes.
Combine cooked shrimp, cooked pasta, vegetables, black olives, and creamy sauce in a large serving bowl.
Garnish with a sprinkle of cracked black pepper.