Why does my hamstring (grade 2 tear) still hurt 7 weeks after the injury?

When a muscle tears, it also tears connective tissue, nerves and lymphatic tissue. As the muscle heals, scar tissue binds the area and then over time, slowly softens. Nerves can take longer to heal and may continue to send pain signals during this time. Make sure not to reinjure the area, as scar tissue is not as strong as the original connections. Use antiinflammatories to help with pain.

You should be under the care of a physical therapist to rehabilitate the muscle. you are still growing and will need continued and ongoing stretching of the muscle and soft tissue structures. Also strengthening of the muscle is just as important to prevent re injury