I have shoulder pain, too. I am actually in phys. therapy for it at the moment- I really need to strengthen and stretch the upper back/neck/shoulders, esp. the trapezius (sp?). They frown at me when I mention the bike and ask if I can get more upright- I already have "comfort" road geometry, so no...and I will do a lot of dull exercises and modify other habits before I give up the bike! Take a look at your work, home, hobby, and child environments- I basically have bad posture and position habits all day long that accumulate into pain on the bike. If I correct those, I will have less pain on the bike. It isn't a bike thing, it is a lifestyle thing. Maybe you have something similar happening?