Technically a hard wood is from a tree whose seeds have a cover. So balsa, is deemed a "hard wood" although very soft.
A soft wood is from a tree whose seeds do not have a cover.
I do not consider pine dense. I do not think it is a good choice for a cutting board, especially end grain. The grain is too open.
For end grain application you want a tight grained species like hard maple, cherry, walnut, purpleheart, redheart, yellowheart, beech.
I think a dedicated lumber yard is a better source than Lowes or Menards. Also if you have a local Woodcraft they have better selection of species, although not cheap.