Preheat the oven to 170C, 150C for a fan-assisted oven, 350F, or Gas 4. Place the cherry tomatoes on a baking sheet lined with parchment. Season with salt and pepper, and drizzle with olive oil. Roast for 15-20 minutes until the tomatoes begin to blister. Keep warm.
Mix the chicken and pesto in a small bowl and set aside for at least twenty minutes.
Preheat an overhead grill to medium, and line a tray with foil.
Place the chicken breast on the grill tray and place under the hot grill for 10-12 minutes, until brown, then turn and cook for another 8-10 minutes.
Serve with roasted cherry tomatoes, pesto, and plenty of bread.