When working out, what is the difference between soreness and pain?

If you do not exercise regularly, it may take a little while for you to distinguish between muscle soreness and pain during workouts. Oftentimes, when I train a new client or even give a regular client a new exercise, I hear a groan followed by, "This hurts!" I immediately ask a series of questions like, "What hurts?," "Where does it hurt," and "How does it hurt?" If the "hurt" feels like a burn and a contraction, you are probably good to go. You just might want to take a breather until you can finish your repetitions. Or if you start to spasm or cramp, take some time to do a little foam rolling (and make sure you are staying hydrated and maintaining a proper potassium level). Keep in mind that when you do resistance training you literally tear your muscle fibers, but this should not cause you pain. It will feel more like hard work and effort. It is normal and requires repair through consuming protein. Exercise is not always comfortable but that does not necessarily mean you should stop. However, if the "hurt" feels like a jab, zap, tear, pull, if it causes you to suddenly stop or drop a dumbbell, and if it prevents you from moving through a full range of motion, it is best to stop the exercise and seek medical attention through a physical therapist or doctor. Bottom line, you know your body better than your personal trainer or the guy on the exercise DVD. So if you know something does not feel right, stop. Take a break, try some stretches, and/or totally exclude the movement. Pain is something in which you might find yourself regularly popping anti-inflammatories. Soreness can come on immediately after exercise or even a few days afterward and can last up to a few days. You will want to give a particular muscle group approximately 72 hours of rest before working out again.  

When working out you will experience Delay Onset Muscle Soreness (DOMS), usually felt 12-48 hours after exercise.  This usually happens when your body begins a new exercise routine that your body is not familiar with.  This will go away after a few days.

Pain is something you do not want to ignore.  It is your body telling you something is wrong.  If you do ignore it, it may lead to more serious injuries in the future.

Soreness from exercise typically shows up 24-48 hours after training and only lasts a few days diminishing over time. Pain due to injury usually occurs instantly is usually a sharp pain or a dull aching pain that doesn’t decrease with time or does not subside with stretching and movement. If at any time while exercising you experience a sharp pain, bruising, heat, swelling, or after a workout, a dull aching pain that doesn’t fade after a few days immediately consult a physician to determine if an injury has occurred. If you experience slight discomfort with movement a day or two after lifting that soon fades that is soreness.

There is a big difference between pain and soreness. Soreness is part of the workout equation and will subside. Pain is your body's way of telling you to take a break. Unless you get paid to play a sport, I do not suggest working through the pain.