An EPIDURAL question?

i had an epidural when i gave birth to my son, which was sunday, my back has suddenly become very sore and stiff upto my neck, and i find it very hard to twist and best over.... is this a normal side effect from the epi, and should i expect it to go away after a little while? i know epis can cause backache for some time, even forever, but im just concerned about it these last couple days.. bit sore! thanks.