Why do muscle pains appear after their work?

Delayed muscle soreness usually occurs after exercise and means the muscles get stronger. Despite the prevalence of muscle soreness after exercise, the exact mechanisms that cause it are not fully understood. Most nowadays believe that this is the result of microscopic tears in the muscles and connective tissue around them as a result of exercise. It is sometimes mistakenly thought that the cause is lactic acid that builds up in your muscles, but it actually disappears from your muscles within about an hour after exercise.