Still awake and  past the dreaded 1.30am, just a threat, sore eye noisy ear but no pain, may'be it will last forever.
Never realised and i'm amazed that there was so many people with "IT", i wonder whether the Romans had it and would it have been called
Clustrious headacheus or lunar epesodicus, may'be that's what spurred the gladiators on, nothing to lose but their painful head.
Could it have started in anglo saxon times when they ran around shaking their heads shouting aarrrgg, I could go on, perhaps you will?.