Yes, that makes total sense. However, the OP isn't complaining about knee pain, so I'm not sure the crank length is the problem. Maybe the seat tube angle is part of it. Maybe she needs to adjust her reach shorter unlike my first guess, but I still think it's more likely a reach issue causing back and shoulder pain than a crank length problem. The cranks could be wrong for her build, but I don't think that's related much to the pain issue here.
Yeah, I guess I have to approach one problem at a time
Also, I'm looking into joining some sort of bicycle club. I am also intimidated by bicycle club people with their sweet bikes and speed So...yeah, hopefully I'll find one this coming spring