Preheat oven to 450 degrees. Line a baking sheet with tin foil.
Fill a medium pot ⅔ of the way full with salted water and bring to a boil.
Place shallot wedges on foil-lined baking sheet. Toss shallots in olive oil with salt and pepper. Roast on top rack for 15-18 minutes.
While shallots are cooking, heat a pan with olive oil over medium high meat. While plan is heating, season chicken breast pieces with salt, pepper, and Italian seasoning.
Add pasta to boiling water and cook according to package directions until al dente (usually around 7-8 minutes). Reserve ¼ cup pasta water.
Cook chicken in pan until done, about 6-8 minutes, tossing occasionally. Reduce heat to medium. Add pesto, sour cream, and cooked noodles to pan. Add pasta water, 1 tablespoon at a time until pasta sauce is creamy and coats chicken and noodles easily.
Squeeze a lemon quarter over pasta and chicken.
Spoon pasta onto plates and garnish with roasted shallots and sliced baby tomatoes. Serve immediately with extra lemon wedges.