Generally, the soreness is from a buildup of lactic acid in the muscle tissue. Lactic acid is a by-product of metabolism and tissue breakdown. You need to make sure that you are drinking enough water during the day so that your body can flush this (and other metabolism by-products) out of your system, and make sure that you are feeding your muscles enough protein and carbs to repair and build new muscle. Gentle warming and stretching of sore muscles prior to working out is important to prevent injury, but only continued working of the muscle will tone it and train it so that the next time it will take a higher level of intensity to cause soreness. Hope this helps! Also, only ice areas that are swollen as heat will only increase circulation to the area and create more swelling. The general rule of thumb is only ice for 48 hours, then you can alternate heat with ice as needed.