If the person were not under stress, the same bodily sensations might not be perceived as symptoms and the person might continue to feel well.

In addition, people are more likely to pay attention to certain bodily sensations such as aches and pains when they are under stress and to think that they're sick.

We think of sensations as being primary, the raw material, the basic building blocks of experience, but there are conscious decisions being made that precede the sensations.