Re- the foam roller.

I like to use a sausage analogy.
Link sausage, patties won't do but they still taste good.

A sausage has a casing that holds in the meat.
A muscle has a fascia that does the same thing as a sausage casing.
The foam roller helps release some of the attachment of the fascia from the muscle, and that makes the muscle easier to stretch.

I'll be at Waffle House if anybody needs me.