Is everything in line??

A medical friend of mine told me last year (after I broke and crushed two of my lower vertibrae) that a back is a bit like a bike derailleur. If everything is in line the bike or your body functions perfectly. Once out of line problems will occur.
Ironically, the only problem I now get is when I go out for a hard ride on my road bike. I'm off to the physio to see if there is anything I can do, but I'm pretty sure I'll just have to put up with the discomfort.