As with a lot of common conditions, there is a lot of ******** spoken.
If you just have muscle pain localised to the back and physio settles it down in a week or so that is fine.
If you have weakness in the legs, cant urinate or defaecate, get to hospital immediately
But most people are in the middle. An MRI is a completely safe radiation free test that gives a diagnosis. I wonder how many of us would take an A/C which was misfunctioning but nobody had bothered to ask WHY? In Germany an immediate MRI is the norm and some 90% of acute back pain patients are back at work in 3 weeks. In the UK MRIs in the NHS are effectively rationed and less than 70% of people are back at work in 6 months. The data is clear.
So please get an MRI and if there is significant pathology see a spinal surgeon. This does not mean definate surgery, but even if surgery is needed, it is not the death sentence suggested above. Many patients benefit from local anaesthetic blocks - injections into the nerves - that can only be done by specialised doctors.
In my experience, the CAA is fairly disinterested unless you have weakness of the legs or bladder/bowel dysfunction and then surgery is mandatory anyway. You need to notify if you have an operation, but I have been involved with a number of pilots and they have resumed flying unrestricted.
If you want advice through this maze, let me know and I will give you some names