contort, move painfully, squirm, distort, suffer, twist and turn, undergo agony, turn with pain, throw a fit*.
Antonyms rest*, be at ease, move easily.
"writhe." YourDictionary, n.d. Web. 19 August 2018. <http://thesaurus.yourdictionary.com/writhe>.
writhe. (n.d.). Retrieved August 19th, 2018, from http://thesaurus.yourdictionary.com/writhe
To twist and turn, as in pain, struggle, or embarrassment:
To move or proceed with short irregular motions up and down or from side to side: