Many different diseases,conditions and injuries can cause chronic pain, from back problems to burns.

VOA: special.2009.02.10

By the way, if we go back to this, another big part of disease--chronic disease that's related to diet, is the physical activity part of the equation.

顺便一说 我们回过去看,大多数疾病,与饮食有关的慢性疾病,与一个关于肢体运动的方程式有关

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

Chronic pain may go away, but it often comes back.

VOA: special.2010.05.04