Decoding the mystery of American pain reveals a warning for the future.

There is an expectation that, on average, pain will increase with age, through accumulated injury, physical wear and tear, and an increasing burden of disease. Consistent with that expectation, pain rises with age into old age in other wealthy countries. However, in America today, the elderly report less pain than those in midlife. This is the mystery of American pain. Using multiple datasets and definitions of pain, we show today's midlife Americans have had more pain throughout adulthood than did today's elderly. Disaggregating the cross-section of ages by year of birth and completion of a bachelor's degree, we find, for those with less education, that each successive birth cohort has a higher prevalence of pain at each age-a result not found for those with a bachelor's degree. Thus, the gap in pain between the more and less educated has widened in each successive birth cohort. The increase seen across birth cohorts cannot be explained by changes in occupation or levels of obesity for the less educated, but fits a more general pattern seen in the ongoing erosion of working-class life for those born after 1950. If these patterns continue, pain prevalence will continue to increase for all adults; importantly, tomorrow's elderly will be sicker than today's elderly, with potentially serious implications for healthcare.