Add bacon, already chopped, to a large pot over medium heat. Cook until evenly browned. Add onion, bell pepper and garlic. Cook until onions are translucent.
Sprinkle flour over and cook for 5 minutes while stirring often until flour mixture is lightly browned.
Stir in chicken stock, a little at a time. Bring to a boil. Reduce heat to low and simmer for 15 minutes.
Add shrimp and cook until shrimp turns pink, about 2 to 3 minutes. Season to taste with salt and pepper.
Notes
you can substitute for a lactose-free milk of your choice - or leave the milk out altogether and just add more stock. But then it's not a chowder, its just a soup. For a heartier chowder, add 1 cup of diced potatoes.