The pain lasted for nearly five years and was often debilitating, intense enough that it sometimes forced Caleb Richardson to his knees.
It left him with an abnormal gait, and he remembers tripping over his own feet and face-planting while walking to class at the University of Pennsylvania.
"I'd lie there, unable to move for 10 or 15 seconds," he said. "I thought, 'Is this is what the rest of my life is going to be like?'
"It was really scary."
It was a difficult place to be for an accomplished athlete, a two-time high school state champion wrestler, to find himself.