More than a quarter of Americans suffer daily pain, but how often they have pain depends on the size of their paycheck. The cost in lost productivity is around $60 billion a year . 

People in households making less than $30,000 a year spend 20% of their lives in moderate to severe pain, compared to less than 8% of people in households earning over $100,000. These findings from a landmark study on how Americans experience pain were published in the Lancet. 

Participants who hadn't finished school reported twice the pain as college graduates. “To a significant extent, pain does separate the classes,” said Princeton economist Alan Krueger who authored the study with Dr Arthur Stone of Stony Brook University.

The type of pain people reported typically fell on either side of the rich-poor divide. “Those with higher incomes welcome pain almost by choice, usually through exercise,” Krueger said. “At lower incomes, pain comes as a result of work.” Blue-collar workers felt more pain on the job rather than off, caused by physical labour or repetitive motion, which offers hope that the problem can be mitigated. 

The findings emphasizes the need for pain preventing measures in the workplace such as better ergonomics,” wrote Prof Juha Turunen, of the University of Kuopio in Finland, in an accompanying commentary to the report.
 
People with chronic pain also worked less, the study found. Other research shows that nearly 15% of the U.S. workforce's productivity is lost to common pain conditions such as headaches and arthritis. Pain has an impact on peoples' emotional states. 

Participants in the Krueger & Stone study said interacting with a spouse or friend lowered their pain, however, those suffering chronic pain tended to socialize much less. They also spend a lot more time watching TV, about 25% of their day compared with 16% for the average person.

One aspect of pain that doesn't distinguish is gender. Men and women were nearly equally likely to find themselves in pain. Another is age.  People reported more pain as they got older, though that pain tended to plateau from ages 45 to 75. “Maybe people reach a point in their career where they move up to a desk job,” Krueger said. “Or maybe they just learn how to cope with the pain.”