I dunno. I've around 8000 miles on my F6B now, and my shoulders and neck still hurt after anything over an hour of constant riding.
I've moved the handlebars a few times...up, out, closer to me, Mustang seat, adjustable hiway pegs, adjustable windshield to eliminate buffeting...
Haven't figured it out yet.
Luckily, my butt, back, knees and everything else feel great after an all-day ride on the F6B.
The F6B is overall more comfortable than my 2002 Night Train. But while the NT hurts me a lil in a few different spots after a long ride, the F6B hurts worse in that one spot than I've ever experienced on a motorcycle. It gets numb, and hurts for days after. Kinda defeats the point of buying the bike for more comfortable, long trips.
So, I get where the OP is coming from.
What I can offer is, if you really dig the bike, try those forward pegs and a different seat. Not the Mustang seat. It puts more bend in the knees. I'm 5'10" and it put my knees right at 90 degrees.