The remedy for tight muscle should take into consideration the cause of tight muscles. If your muscles are feeling tight due to exercise, perhaps you began a new regimen or tried some new moves, then consider how much flexibility training is in your schedule. In our busy lives, we tend to leave our workouts and force our muscle to cool in a contracted state. Spending a few moments post-workout to stretch can result in more supple muscles and better overall performance.
A warm, not hot, bath can also help ease some muscle tension. Make sure to cap your bath at no more than 20 minutes, since longer baths and showers have been shown to deplete the skin of essential moisture. If the tightness has been ongoing since beginning a workout, consider seeing a massage therapist to help ease the tension and release tightness in the fascia surrounding the muscles.
If muscle tension has no foreseeable cause (new workout regimen, higher stress levels) make an appointment with your physician just to get everything checked out. Never underestimate the importance of flexibility training to keep muscles in optimal performance condition.