My legs hurt.
You go to the gym or try a new exercise and you say the next day i felt okay, but the day after i could barely walk cos my legs are so stiff and sore.
Sound familiar?
Delayed Onset Muscle Soreness (DOMS) - although still not fully understood - happens when the muscles are loaded on an eccentric muscle contraction (when the muscle is lengthened). At a microscopic level the muscle filaments tear and the muscle membranes become damaged causing pain, tenderness and swelling.
Another theory is the release of oxygen free radicals that occur through inflammtion. They damage cell membranes too.
The possible reason the pain occurs 48 hrs after the exercise is that the cells die in that time. When muscle tissue is being regenerated, the nerve endings are stimulated, causing pain.
As for reducing the effects - good luck :)
The best thing to do is train (:( for some) Start slow and build up. The muscles become accustomed to training and it becomes easier.
Stretching does not prevent nor treat muscle soreness.
A theory is that soreness is part of the natural process of muscle hypertrophy (increase in muscle mass).
Rock on!