Several years ago, a small stone( medium sized but it had a sharp end) had fell on my mother's head during building construction. There was bleeding and sutures done. Doctors mentioned nothing to worry and it's fine. This happened more than ten years ago. But my mom gets that sharp lightining kind of head pain on that injury side. My mom got a MRI scan as well and doctors mentioned it's all fine. But she still gets the head pain. What can be the reason and what else should we check? Can someone please suggest