Now the chest pain was with me every night and day. Sometimes it came over me when I was watching our little girls, making me terrified that they might watch their father collapse in front of them. At night I sat up with it, trying to decide whether I needed to rush to the E.R. again.

But I was also deep into self-doubt about the reality of my experience. The pain was crushing, but what were mere feelings set against the certainties of so many doctors, the negative readings of my blood?

The tipping point was my session with the head of infectious diseases at a major hospital, an appointment that took six weeks to get and that lasted all of 15 minutes. He listened to an abbreviated version of my story, sighed and leaned backward in his chair.

“Look, we’ve done everything for you,” he said. “If you had an infection, we’d catch it.”

“So what does that mean?” I said weakly. “I’m just in so much pain, Doctor. Can it really all be … stress?”