Simple:
* She agonized over the decision for days.
* He agonized in pain, unable to move.
Descriptive:
* The artist agonized over the perfect brushstroke, erasing and reworking the canvas for hours.
* The witness agonized under the lawyer's relentless questioning, trying to remember the details of that night.
Figurative:
* The city agonized under the weight of the oppressive heat.
* The trees agonized in the wind, their branches thrashing wildly.
In dialogue:
* "I'm agonizing over this choice," she whispered, her voice strained.
* "Don't agonize over it," he said, "just make a decision and move on."
Remember, "agonized" implies a great deal of mental or physical struggle, so choose your sentences carefully to convey that feeling.