Momz- I am sorry i don't have much time to write just now, but I am thinking of you.
Olecyn is right, you must try to relax...once the nerves are fired up it can take a long time to get them calm.
I think the chin tuck exercise is a way to measure if your abiltiy to stretch (or not) is from nerve compression or muscle tightness... i have posted about this page before, and reading about the general category of neurodynamics might be a place to start.
slump test
I will also pull up an old thread i referenced this test in.

take care.