the soreness tends to go away with regular riding...and returns if you haven't ridden in some time.
as for finding a comfortable saddle, there are endless threads on the topic on bike forums (like mtbr.com) and the unfortunate answer is that you have to try. That said, there are certainly different general shapes, and some (like Specialized) come in widths designed to match the width of your sit bones.
IMO wide cushy saddles will inhibit your riding, unless you are just going out for a leisurely few miles on a comfort bike, then don't bother. Good design, fit, and adjustment, along with lots of riding, are the keys here, and the former may take some trial and error to find, so I'd recommend accepting some failed experiments as a possibility. Don't get discouraged, just be systematic in what you try (and what you try next). A good bike shop should be able to help you with these choices (again - lots of padding is not the answer), and a really good bike shop should allow you to trade in a saddle that didn't work out (they can typically return them to the manufacturer as a warranty issue).
I've had lots of good luck with WTB and Specialized, both of which make a variety of saddles, but your comfort may vary.