What is the worst physical pain you've ever been in?

its hard to really decide but I think when I was admitted into hospital as a teen when it was thought a aneurysm burst in my brain. Felt like my brain was swelling so much that it was pressing so hard against my skull that the skull itself was cracking.
Luckily it never burst though and I never really got many answers on it or maybe i did but was so doped up on morphine I didnt even let it register