Delayed Onset Muscle Soreness DOMS typically is a phenomenon of muscle pain, soreness, stiffness or swelling that is felt due to microscopic tearing of the muscle fibers within 12-48 hours after exercise or sports activities. It is caused by Lactic Acid buildup during exercise. However, since lactic acid disperses fairly rapidly, it subsides pretty early – say within 2-3 days. The amount of