Originally Posted by BSousa
If im not mistaken is because of the lactic acid produced during exercise (needed) that remains there after exercise. Passive stretching after exercise while still warm helps reduce this. Do note that most back and shoulder paisn don't originate on the muscles but on some other problem (bones, tendons, protective menbranes (specially on back and chest).
Do a search in google for "Lactic acid muscle soreness" and you should get some ph.d's explanations...
I'm afraid you are mistaken. Lactic acid makes your muscles burn during exercise, but delayed muscle soreness comes from tiny tears in the muscles that occur during intense anaerobic exercise. The soreness goes away when the muscle has repaired itself.