I ride a steel bike & I love it. It is custom, so the fit is perfect BUT I find that the road feel is superior, the cornering is more precise and it will bend before it breaks. The new steel is lightweight and responsive. I haven't heard that steel is out of fashion.

It sounds like you need to be fitted by your bike shop. Ask for somebody who rides and tell them what is going on with you. They can put you on rollers and look at your riding habits. You may need a more upright position to alleviate the pain between the shoulder blades, but it's hard to tell without watching you.

Components - I ride Chorus Campy because it seemed more female friendly - the gears were easier to shift than Record and I much prefer Campy over Shimano for quality & precision shifting.

I also love Continental tires. They have a nice road grip without sacrificing rolling resistance.

BTW, we're about the same size - I'm 5'5".