Originally Posted by qclabrat

not a touring bike, but on my backup mtb, I had a very short stem for tricky riding. After an hour, my lower back was very sore. The following week I switched out a longer stem and it was night and day. Your stem is already fairly long, try sliding your saddle forwards or backwards to see if it helps. Even after a proper bike fitting you may need small incremental adjustments. I prefer playing with the seat before buying a new stem.