The soreness is due to lactic acid build up in your muscles. Lactic acid is used as a substitute for oxygen in the body. When your muscles do not recieve enough oxygen during fermentation, lactic acid is used instead. Depending on the difficulty of the exercise, the acid will remain in your muscles for several days, thus making them sore.
Lightly exercising and stretching the sore muscles will increase blood flow to the area and the lactic acid will be washed away.
But hey... maybe we are bolth right.