On a scale of one to 10, how much does it hurt? That’s the most advanced tool doctors have for assessing pain. “It’s challenging,” said Dr. Brian Pierce, a primary care physician at Midcoast Medicine in Rockport and president-elect of the Maine Medical Association. “Chronic pain is one of the hardest things we do.” One reason is that there’s no test for pain – no full-body scan or blood analysis that can show whether a patient has it or how bad it is.