Disc Prolapse (or herniated disc)
The term 'disc prolapse' is commonly used to describe the appearance of an MRI scan or CT scan.
In spinal surgery the term we often use is 'Treat the man not the scan'. So, if the symptoms you have are mainly in the back the scan appearance may not be relevant.
Sciatica generally is where the pain goes from the back and down one leg. The leg pain may be more 'bothersome ' than the back pain.
Have a look at the section on sciatica.