I dunno. I used to be flexible as hell, but was also too damn broad across the shoulders to get everywhere. That was even before I started lifting seriously; lifting just made the area I couldn't reach bigger.

Somewhere around 16 I hit a spurt and suddenly couldn't reach a zone between my shoulder blades. It was maybe hand sized. In my twenties, it was about an inch or two bigger, but I could still do all the stretches fully before lifting, and that included shoulder stretches where I could end up almost flat with my arms behind me.

Nowadays, I'm just old and stiff, and can't scrub anything right on my back.