Muscle pain can be just as painful but rarely shows on MRIs.

Everyone is different too, my dad has hardly any disks left due to degenerative disk disease , but luckily only some discomfort and muscle pains , no major nerve pain from it..
Yours mentioned "impression on the thecal sac but no cord impingment or spinal stenosis".
from what I have read that usually isn't a cause for pain..
but might be or might not be..

On avg what is your pain level?

Did you have any injuries- strains, falls etc- long ago from cheerleader or gymnastics?
Did you see anything interesting in the link I posted earlier?