Ever have a great workout and then the next day you're sore in an area that you didn't really work? Or perhaps you are in the middle of a workout and are noticing pain or burning in muscles that shouldn't be feeling the particular exercise, such as your lower back aching while doing an abs exercise. This may be a sign of improper form when lifting weights or performing an exercise. Unexplained aches in your back and neck, or general joint pain, can be signs that you have overstressed your joints or exercised in poor form, causing your body to overcompensate and recruit other muscles to help do the work.
How to prevent it: Always make sure that you're exercising with perfect form. If you can't perform an exercise with proper form, it's a sign that you either need to decrease your weight or modify the exercise.Burning Sensations in Muscles
When people say "no pain, no gain" in the gym, the pain they're talking about is actually the burn you feel in your muscles when you really push into and past fatigue. (As you've already learned, real pain is no gain to anyone.) This burn is an unpleasant—but normal—sign that you are working. See, when our muscles use energy, they release hydrogen ions or protons. When doing heavy or prolonged exercise, the protons in your muscles actually accumulate faster than your body can release them, making your muscles burn. This burn is a sign that you've reached muscular fatigue or "overload," which is a necessity if you hope to build stronger muscles.
How to prevent it: You can prevent this by working out at a lower-intensity, although every few days it's good to "feel the burn" because you know that you're really working those muscles in a way that will help them get stronger!
Active Recovery, from About.com: Sports Medicine
Don’t Be a Sore Loser - Dealing with Muscle Soreness, from ACEFitness.org
Muscle Cramps, from U.S. National Library of Medicine National Institutes of Health
Muscle Pain and Soreness, from About.com: Walking
Muscle Pain and Soreness After Exercise - What Is Delayed Onset Muscle Soreness, from About.com Sports Medicine
Sore muscles after exercising, from ScienceDaily.com
Sore Muscles? Don't Stop Exercising, from WebMD.com
Stretching Out Does Not Prevent Soreness After Exercise, from ScienceDaily.com
What Makes Muscles Burn?, from Prevention Magazine