Combine chicken broth and saffron in a medium saucepan and bring to a simmer. Do not boil. Keep warm over low heat.
Rinse and pat dry the shrimp with a paper towel and set aside.
In a large paella pan or skilled, heat 2 tablespoons of olive oil over medium heat. Add shrimp; saute for 2 minutes. Season with salt and pepper. Remove from skillet saute for 3 minutes, stirring occasionally to keep from burning. Remove from skillet and set aside.
Add chicken to the skillet and cook for 5 minutes, stirring occasionally. Add onion and red bell pepper, cook for 5 minutes. Add garlic, cook for 1 minute. Add rice; cook for 2 minutes. Stir in hot chicken broth, cooked chorizo, tomatoes, lemon juice, paprika, and parsley. Reduce heat to medium and bring to a simmer. Cook stirring frequently for about 10 minutes until the rice as absorbed most of the broth and is almost tender.
Arrange cooked shrimp over the rice (optional). Scatter the peas over the top of the rice. Reduce heat and cover with a lid and cook for 5-10 minutes. Removed from heat and let stand for 10 minutes.
Garnish with red bell pepper slices.