That sounds terrible, Sciatic pain down the leg is relentless and draining, i know. I'm 63 and long ago came to the conclusion Doctors and back pain is just about a waste of time, as you say its a silent pain and they can't see either.
I'll never proof it but i believe my troubles were probably started by spending far too much time bouncing around in my dads early Land Rovers on the horrendous bench seats in the back while twisting to see where we were going. That and a life time of groundwork, i only have to look at a shovel nowadays a i have pain.
I have a Osteopath i see every 3/4 weeks, he's a ex stone mason believe it or not, been to numerous Chiropractors and Osteopaths over the years and find they all start with good intensions but when you go regularly as a maintenance measure over time they loose interest and start to just go through the motions although the current one is still determined to help and has achieved more than any other, ironically he a big Land Rover nut as well.