The type of epidural that both gwennan and M56789 are talking about are not the same type of epidural injections that are given for spinal issues.
They are talking about an epidural given for anesthetic pain relief during childbirth, i.e. labor and delivery. This is an injection of anesthetic that totally numbs the woman's body from the waist down.
ESI are epidural steroid injections that given for spinal pain from a medical spinal problem. This type of injection involves a small amount of lidocaine and a steroid. After it is given, you have full feeling from your waist down, can get up and walk around and function.
Not so, immediately after being given and epidural during childbirth.
As for the problem they are having, it is quite possible that when the epidural injection was given, the long needle that was used may have hit on the vertebrae and bruised the bone of the vertebrae.
If that is the case, it can take several years for the pain to go away.
I would suggest that at this time, you both consider seeing a spinal specialist and see if with an MRI or CT they can determine what is causing the pain.
It could just be a coincidence and that you already had a spinal problem and just had no symptoms. After childbirth, the changes in the body that occured during pregnancy may have contributed to now being symptomatic instead of having no symptoms.
You should at least be able to get a diagnosis about what is causing the pain and you can only get that by seeing a spinal specialist.
Good luck
Fran