Sudden onset lower back pain needs an MRI for diagnosis. Early diagnosis and treatment massively increases the proportion of sufferes who get back to work. Treatment varies and there is little evidence one route is better than another so I would recommend you demand to be seen by a consultant who only does backs - a spinal surgeon - not an orthopaedic surgeon or other generalist, and do as he says!
If you have difficulty passing urine or defaecating you need to see someonec immediately, if not then within 'days'
This is very common and although not everyone remains pain free for life, it is unusual for it to effect the ability to work if you are treated promptly. In my experience regulators are little interested provided you do not lose power in your legs. Pain may prevent you flying but that is another issue
good luck