Hi Liza, that pain does sound real nasty when your trying to sit, so i am wondering if a different approach of sitting might help, what i mean is we tend to lean forward when sitting, which of course stretches our lower spine the lower we go, so when about to sit, keep the feet further out from the chair than one would normally and leaning the spine backwards more so, then lower down gently onto higher chair, just a different angle of the spine may help, i hope i have explained myself properly.
good luck anyway.
Brian