Why is mind chatter disconnected from relaxed body in practice?

I can achieve complete physical relaxation in my body—my limbs are heavy and still—but my mind continues its relentless chatter. There is a disconnect between my body and my mind. This separation hinders my focus and increases my overthinking. My name is Saurav, born on 11th September 1984. Time: 6:45 PM. Location: Kolkata. How can I bridge this gap and get my mind to follow my relaxed body?