Endorphins do exist!

Is the story about endorphins really true? After today's long run, I think it might. After returning from Portland last Monday, I had pain in my back, which felt like muscle pain you get from sitting in a bad chair for too long. However, it got worse in the days after, and I also developed a rash. The doctor concluded it was "gordelroos", which is some sort of recurrence of chickenpox. You don't become as sick as from the original disease, but it still very painful. The last couple of nights I therefore had pain while sleeping.
Now, this morning it was finally time for a proper long run (>30k), so I wasn't sure whether it was such a good idea with my blistered back. My apologies if this becomes a bit too distasteful. Steffi and nevertheless set out, and instead of becoming worse, the pain completely disappeared. Of course, by the end of the long run some other, more familiar pain started to replace it, but fortunately none of the aches that have plagued me in the last half year. So, were the endorphins suppressing the pain?

A more general update: this week was a good week of training, and I start believing in the marathon again, which is now just slightly over a month away. Next week I will run the Bommen Berend half marathon, which should be a good indicator of where I stand. But before that Steffi and i will go to Brussels to watch the diamond league. Unfortunately, Usain Bolt is injured, so will be absent, but there are plenty of other running stars to look out for.