Cook penne according to package directions. Drain and set aside.
In a large skillet with a lid, heat olive oil over medium-low heat. Add in garlic and red pepper flakes, cook for 2 minutes or until garlic begins to soften.
Add in mushrooms, tomatoes, salt and pepper. Cook for 5 minutes, or until mushrooms begin to release their water.
Turn heat up to medium-high and add in shrimp. Cook for 1-2 minutes, or until shrimp are pink and opaque. Remove from heat, add in spinach and cover skillet. Let spinach wilt for 2 minutes.
Remove lid and place skillet back over low heat. Add the penne, Greek yogurt and pasta sauce. Stir until sauce is mixed well and all pasta and veggies are coated. Heat until just warmed through. Divide into pasta bowls and serve topped with parmesan cheese.