(Spoiler: It’s not as bad as the title sounds.)
Just as the mind needs a few days to get accustomed to bicycle touring life, so does the body.
Barring any injuries or exceptional conditions, the most uncomfortable period of a bike trip is always days 2-4. Probably largely because I don’t tend to practice or train much (or at all) before starting.
The first day is all joy and happiness, with an overoptimistic sense of “nothing can stop me now”. But even an easy start takes its toll. On the second day I always have slight discomfort and ache in the lower back, wrists and ankles. The saddle in particular is not my friend during this time. Basically all of the contact points with the bicycle complain under duress, and this lasts for about three days.
By the fifth day of cycling, all pain and discomfort is gone and stays gone. This has happened on all four of my previous major tours so far, and it happened again exactly the same way on this one. The body simply adapts to the strain.
In the meanwhile, I've crossed the border into Norway. Because the stores were closed on Sunday, I camped for two nights near Karasjok to refill my supplies. When I started towards Kautokeino, I was bathed, rested and well fed. And generally feeling rather good about my life choices.
World, here I come!