Serious post-workout soreness can derail any fitness goal. A little delayed onset muscle soreness, aka DOMS, is a good thing. It means you challenged your body, and the muscles are repairing themselves in a stronger way. However, if your soreness lasts for longer than 48 hours and prevents you from being able to wash your own hair, unclasp your bra, or sit down without groaning, your body is telling you that you overdid it. But don't give up on working out; a little light cardio helps relieve the pain. Next time you work out, don't push yourself so hard.
For more on this read How to Ease Muscle Soreness.