Same here, I had an excruciating experience with getting the epidural and my son is now 3 months as well and I can’t even begin to explain the back pain I’ve had since then. My doctor wants me to get an X-ray because she says that doesn’t sound right. I think you should see a doctor and get checked !!
Go to hospital. Could be an epidural hematoma or cerebral fluid leaking from thick needle creating a void in the disc that did not refill properly or , in the case of the hematoma, it’s a bruise on the spine causing neurological problems. They need to assess and maybe do an MRI.