Does amitriptyline calm down overactive nerves when used for pain ?

Yes, it helps so: Amitriptyline is often used for pain conditions. In neurology, it is used to reduce the pain of neuropathy, frequent headaches, carpal tunnel syndrome, trigeminal neuralgia and back pain. It is good to think that it reduces or calms the pain response by acting on nerves. It is not a pain medicine for all uses however. It would not be useful for a broken arm or sprained ankle.