The relationship between pain and depression how one affects the other isn't always clear.

Even a pure true feeling of the difference between pleasure and pain is denied me.

The second sought to uncover the relationship between sleep and pain.

Whatever her plan had been, it floated just out of reach somewhere between pain and shock.

"Someone told me there was a difference between pain and injury," Woods said.

The difference between pain and injury is the thing here.

One criticism is the obscure relationship between pain and gain.

The interplay between sleep problems and pain requires treatment of both.

For a second she was caught between pleasure and pain.

The trick was, of course, walking that fine line between pain and death.