Too much of anything isn't good for you. When it comes to stretching, one of the most important things you can do is listen to your body. As you’re progressing through the stretch, the area you’re stretching should start to feel better, not worse. Focus on a high quality of movement and don't push through into a position that’s painful.
If you’re just getting started with a stretching program, rather than over complicating things, keep it simple. Five minutes of stretching each day goes a long way. :)
For some great advice on how to progress your flexibility, check out these stretching tips!