Cook pasta according to instructions. Set aside.
Place oil in large saucepan with onion and garlic. Cook over medium-low heat for 5 minutes until softened.
Add shrimp and cook about 4 minutes until shrimp are cooked and turn pink, stirring occasionally.
Reduce heat to low, add tomatoes, salt, crushed red pepper, balsamic vinegar, basil and stir to combine. Cook for a few minutes until tomatoes soften.
Add pasta to saucepan and mix again.
Turn heat off and add mozzarella. Mix well. You don't want the cheese to melt, just to blend in with the flavors. Serve immediately.