Chronic pain has this one undeniable fact: More often than not, it is untreated or under-treated. In a survey last year by the American Pain Society, only 55 percent of all patients with non cancer-related pain and fewer than 40 percent with severe pain said their pain was under control. Chronic pain is second only to respiratory infections as a reason to seek medical care. Yet because physicians often do not take a patient’s pain seriously or treat it adequately, nearly half of chronic-pain patients have changed doctors at least once, and more than a quarter have changed doctors at least three times.