When did you get the Madone? If it's a 2011 or 2010, I think it came with a Bontrager Affinity saddle. probably 144 mm. if you look at the saddles for sale at your LBS, you might be able to figure out which model you currently have (R, RL or RXL) and which width. Then have them measure your sit bones to make sure you have the right width.

Is the soreness caused by chafing or too much pressure? Either way, if the saddle is the correct width, changing the position slightly might help.