I'd say the strongest pain I ever felt was when I broke my toe. I somehow stubbed it really hard on this small step leading up to my bathroom and it hurt so much that I was involuntarily screaming and shouting for just under a minute. It's the only broken bone I've ever had, even though I've had a few really bad falls that could easily have broken bones (eg rolling my ankle badly while pole vaulting, falling down a flight of stairs and landing on my finger and bending it back - it is actually still a bit swollen after several years). So for me to have actually broken something it must have been a really bad impact.
Worst was this migraine I had last year because I was in intense pain for longer than my toe injury and I also felt extremely nauseous. It was the worst headache I'd ever had plus I couldn't even lie down or go to bed because I was bent over the toilet feeling like I was going to throw up at any moment. To make things worse, I couldn't throw up which probably would have made me feel better. It went on for about 4 hours until I finally felt well enough to go to bed and sleep. Luckily I was fine when I woke up.
Worst was this migraine I had last year because I was in intense pain for longer than my toe injury and I also felt extremely nauseous. It was the worst headache I'd ever had plus I couldn't even lie down or go to bed because I was bent over the toilet feeling like I was going to throw up at any moment. To make things worse, I couldn't throw up which probably would have made me feel better. It went on for about 4 hours until I finally felt well enough to go to bed and sleep. Luckily I was fine when I woke up.