Nobody knows what causes DOMS, all we have at this juncture are theories, anyone saying that they know are tools.
what we know is that there are nerves in the muscle, but these particular nerves are not the nerves that identify pain.
so, the common excepted theory of the educated person is that DOMS is not a measure of muscle growth or its byproduct "strength".
DOMS is a result of doing a movement or exercise after a prolonged break, where the tendons, ligaments and bursar have been subjected to movements their not use to, as with everything you nimrods, the severity and duration of pain would be different from one person to the next.
the only true measure of growth is progression you dumb fucks.
nothing else is possible.