Common Scenario - we do a 100 lb lift, or a 20 mile run, then the next day, we can barely hold a pencil or walk up some stairs, (then the person in the elevator thinks, "what a lazy ass for taking the elevator to the 2nd floor!")
Usually around 24-48 hours, we experience a soreness called - Delayed Onset Muscle Soreness, or DOMS.
This is because we get tiny tears in our muscles when we have an intense workout, and the muscle is trying to repair itself. It sounds awful, but its actually a good thing. When our muscles repair themselves, new and stronger muscles are grown = a better, stronger body.
Now the Burning sensation you get in your muscles During your workout is due to acid buildup. There are many different types of acid that gets sent to the muscle, but Lactic acid buildup is the one people mostly talk about.
I don't like to get to "chemically definitive" about how things work because I feel the topics themselves are overwhelming enough, so in a nutshell,
When we work a certain muscle, the body has to send 'Extra' nutrients to power that muscle being used. However when we're done, the body has trouble "flushing" out all the nutrients it has just sent to that muscle. Just like a traffic on a freeway, which will take some time for it to be back it its regular levels.
Now the last 2 sentences are still debatable. Some believe what I had just written (which I believe) others believe that once you stop working out Lactic levels return to normal right away.
But either way here is my favorite ways to recovery from a hard workout.
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