The freezer thing is a bit of a myth. I mean, it kinda works but only because you have to air the jeans out after. Just air them out and it should do the trick. Maybe a quick spray of febreeze or something as well helps.

You’re buying the wrong size jeans. Your jeans should be a tad snug (but still easy to button) when you first try them on. After a one or two wears they will stretch to your body’s shape.