Preheat oven to 375F.
In a large, heavy-bottomed skillet or Dutch oven, heat the olive oil over high heat until smoking,. Season the ribs with salt and pepper and cook them over high heat until deep brown all on sides, about 15 minutes total. Remove the short ribs to a plate and set aside. Add the carrots, onion, celery and garlic to the pan and cook over high heat until browned and softened, about 4 minutes. Season with salt and pepper and stir in the red wine, tomatoes and juices, chicken stock and herbs, scraping the bottom of the pan with a wooden spoon to dislodge the brown bits. Brin the mixture to a boil and return the short ribs to the pan. Cover with aluminum foil and place in the oven. Cook for 2 hours, or until the mat in very tender and literally falling off the bones.
To make the gremolata: in a small bowl, combine the parsley, lemon zest and horseradish and toss loosely by hand.
Place one short rib in each bowl, top with a little of the pan juices and a handful of the gremolata, and serve immediately.