Cook penne according to package directions. Drain and set aside.
In a large skillet with a lid, heat olive oil over medium-low heat.
Mince garlic and add to skillet, along with red pepper flakes; cook for 2 minutes or until garlic begins to soften.
Chop mushrooms and tomatoes; add to skillet, along with 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 skillet from heat, add in spinach, and cover for 2 minutes or until spinach is wilted.
Remove lid and place skillet back over low heat. Add the penne, marinara sauce, and yogurt. Stir until sauce is incorporated and pasta and veggies are well coated. Heat just until warmed through.
Top with Parmesan and serve with grapes on the side.