Sciatica can be caused by spine issues. If you have bulging discs, one can be pressing on the sciatic nerve. If you are in a lot of pain, I would suggest you seeing an orthopedic doctor who specializes in the back. An MRI of your spine may be suggested as to see why you are experiencing the pain and exactly what is causing it.
https://connect.mayoclinic.org/discussion/how-can-i-tell-if-i-have-sciatica/

