I own a 1999 Peloton. I love the days when I can take it to work through the slice-and-dice of city traffic.

Upper body pain is tough to diagnose on teh Interwebz. It's not like knee pain which can be traced to specific things based on its specific location. It's likely to be something with the bar location--too high, too low, too close, too far--but it could just as easily be position and rotation of the levers, or even something rider-induced, like muscle tension or the way you hold yourself on the bike, or use of a backpack or messenger bag.

Fortunately, the Peloton uses an older-style quill stem, which is easy to adjust for height. There's a 5mm bolt dead center in the top of the shaft that extends down through the head tube. Loosen it and you can move the whole assembly up and down. You'll need to respect the markings on the shaft of the quill for minimum insertion (maximum height).

While you're messing with it, put some grease (yes grease) on the quill shaft to help prevent it from corroding in place. If it doesn't move after loosening the bolt, this corrosion has already happened.

Should you need to adjust the reach, your best bet is to replace the quill stem with a quill-to-threadless adapter, (about $15) then use a contemporary stem ($20 and up) to lengthen or shorten the reach. This is what I've done on mine. The alternative, a different quill stem, is difficult to source these days. They're available mail-order, but you'll already need to know the correct length to order. It's far easier to get local fitting, service and advice with the quill adapter and threadless stem.

Since your local shop doens't seem too enthusiastic about helping you, find another. Austin has plenty.

There's also the Austin Yellow Bike Project, a community bicycle organization: