Apple products are very high quality, but not all software is created equal, and eventually every computer is bound to glitch out from time to time. When a mac glitches it can cause battery issues (like it tells you you have more or less percentage of power than you actually have) or sound issues (no sound even when you turn the volume up). These issues and a multitude of others might be solved by a simple restart, but if that doesn't work, try this method which comes direc