A few years back, I had a collapsed lung surgically repaired. Basically, they chemically scarred the exterior of the entire lung and the surrounding tissues so they fused together.
Fun times.
It sucked, but it didn't seem like a "worst in your life" kind of suck. Spent a week wandering hospital halls pre-op (holding a box of my own fluids). Another half-week post-op (now, with two boxes and a bag of said fluids, and chock-full of Dilaudid). Then, they sent me home with a bottle of Percocet and a plastic air-bong to do breathing exercises with. A week after getting out, I was starting to feel generally human.
And then I sneezed for the first time.
At that moment, I couldn't quite recognize it as "pain" -- it was just an all-encompassing instantaneous sensation. The world just...went away. Whited out.
Went silent. About five or ten seconds later (I think), things faded back in. All that was left of the pain was a deep ache in my chest, and a whole-body "holy shit!"
So, yeah; worst pain of my life basically rebooted me like a computer.