Commuting - comfortable commuter

I commute on a ten-speed with drop bars but have been having trouble with my back and shoulders
I hope to find a comfort-hybrid type commuter without giving up too much on speed and performance...I have been looking at some of the Bianchi bikes like the Bergamo.
any suggestions?...

You can always put upright bars on the ten speed with a very short stem and change the saddle. Not much difference from a hyprid.

Have you tried tweaking your fit on the 10 speed?
In my case, upright style bikes actually cause more issues with my lower back. The weight is not distributed and all on my rear. Thus, the back issues. Plus, the lack of aerodynamics automatically slowed me down.

Why buy a whole bike when all you need is different bars (and
maybe an adjustable stem) and / or a different seat/saddle.

It seems that the bike you have now is Ok it just needs "adjusting"
to fit you at your present age/condition. Sitting more upright will
resolve your discomfort so why buy a whole new bike that may
not be as good as the one you have???

ohhh
my mistake, I ride a 1979 Schwinn Varsity and was looking for a replacement bike, but wanted something that had a more upright, comfortable position. So I am going to buy a bike soon.

For longer rides, I find a bike with drop bars to be the most comfortable possible. My commute is 15 miles each way, and I ride a touring bike, with drop bars - most important thing is to get the fit right.
If I try riding a more upright bike that forces me into one position for long periods of time, I end up much less comfortable.

ohhh
my mistake, I ride a 1979 Schwinn Varsity and was looking for a replacement bike, but wanted something that had a more upright, comfortable position. So I am going to buy a bike soon.
No problem replacing the handlebars and getting an upright position on a Schwinn Varsity.. I just did it last week on a Schwinn Varsity that I picked up for $5 at a garage sale. I had some spare upright handlebars laying around and took the handbrake levers and cables off another $5 bike that I got for my wife to decorate the garden with flower baskets and vines. If you don't have the handlebars and brake levers on hand a garage sale oldie should provide them cheaply. The labor took me all of 15 minutes.

...was looking for a replacement bike, but wanted something that had a more upright, comfortable position. So I am going to buy a bike soon.
Have you considered a touring or cyclocross bike? More relaxed geometry than a road bike and very comfortable.

The drops to flats conversion is pretty standard amongst older touring style riders and predated any of this "hybrid" nonsense. It will place your default hand position much closer, near to your current tops position.
If you want to see some alternative styles of "flat" bar, check out the Nitto bars at Harris or Rivendell stores.

ohhh
my mistake, I ride a 1979 Schwinn Varsity and was looking for a replacement bike, but wanted something that had a more upright, comfortable position. So I am going to buy a bike soon.
I think we're missing the important point. He wants a new bicycle. We can all appreciate that. Who doesn't long for a new, sleek, shiny bike? :) In that case, cyclocross and touring bikes make good commuters as well as bikes set up for commuting like the Kona Smoke or the Specialized Sirrus. The Smoke's actually a mtb while the Sirrus is more roadish.

FWIW, I ride an IRO Rob Roy cyclocross bike. It's steel, fixed gear and has risers although I'll be putting on bullhorns soon. I commute w/ it and have done longer rides on it w/ no comfort problems. I'd suggest the Rob Roy if you want a SS/FG cross bike.