Pain is more than just a complaint -- it's a public health issue. And the time has come to do something about it. So concludes a new report from the Institute of Medicine, written at the request of the Department of Health and Human Services. The report, mandated by the healthcare overhaul law, estimates that chronic pain costs between $560 billion and $635 billion each year in medical expenses and lost productivity. But, it adds, pain is also personal, affecting each person individually. One-size-fits-all approaches won't address the problem, the report concludes. Chronic pain, from cancer to back pain, is influenced by heredity, stress, depression and other factors, and sometimes lingers after the underlying condition is treated because of changes in the nervous system. So pain can be a disease in and of itself. Yet, the report points out, few medical schools require, or even offer, courses on pain.