Squirm in pain is an expression used to describe the physical act of writhing or contorting one's body due to intense discomfort or pain. It is often used to describe a person's reaction to a painful stimulus, such as a bee sting or a burn. The term is also used figuratively to describe a person's emotional distress or anguish. The crossword solution WRITHE is a 6-letter word that accurately captures the meaning of the phrase 'squirm in pain'.