When working out, it is normal to feel fatigue and muscle burn with strength/endurance training. But you should be aware of the difference between muscle fatigue versus pain. If you experience pain while working out, you should stop the activity you are doing. Pain can develop from inflammation, bad form with exercise, and overuse of a specific muscle. Pushing yourself too far could lead to an injury that can prevent you from doing the sports or exercises you enjoy. Use ice to decrease the pain developed from the exercise. If your symptoms do not lessen with ice and rest, visit your local physician or physical therapist.