Heat grill. Brush cut sides of tomatoes with 2 teaspoons oil and grill, cut side down, without turning, until charred, about 10 minutes. Remove from grill using spatula, transfer to cutting board, and chop. Set aside. Toss shrimp with remaining 1 teaspoon olive oil and sprinkle with 1/4 teaspoon salt. Grill, turning once, until cooked through, about 6 minutes. Set aside.
Bring a large pot of salted water to boil. Add corn, and cook 3 minutes after water returns to boiling. Using tongs, remove corn from water. Add pasta to boiling water and cook according to package directions for al dente, about 9 minutes. Drain well.
While pasta is cooking, use a large knife to cut corn from cobs. After draining pasta, add chicken broth to pasta pot and bring to a boil. Add corn, pepper, cooked pasta, diced tomatoes, cream, chipotle-pepper sauce, and remaining 1/2 teaspoon salt. Toss pasta with grilled shrimp. Sprinkle with chopped cilantro, if desired.