Endurance athlete Kevin Humphrey was used to discomfort. He regularly participated in ultramarathons and other intense events. Swimming, biking and running dozens of miles at a time was standard for him. His two young sons also kept him active even when he wasn't training. But in January 2024, a persistent back pain kept bothering him.  The pain "just would not go away," Humphrey said. He couldn't sleep on his back. At the same time, he started coughing. He was diagnosed with pneumonia, but his