I believe they're cartridge bearings. That said, having the cones overly tight will affect the wheel's spin with cartridges also. I've had the same problem with a Miche hub (cartridge) and an inept mechanic. Get some cone wrenches and take it apart. If it's loose ball, you know what to do. If it's cartridge, just adjust the cones so they're not so tight. And if that doesn't solve your problem replace the cartridges.
And don't use that LBS anymore. There's nothing they can do for your fix that you can't do better yourself given the proper tools, and after paying them to screw your ride up a few times you will have spent enough to buy the tools you need.