When I'm running my abdomen always hurt. Many said that I lack of water. But when I take enough of water, I still feel the pain? Why? How to prevent?

Stop running. "many" are incorrect. You should stop running and get a comprehensive medical examination as well as a GYN exam. Take nothing for granted and only accept your physician's advice.
See below. There are a number of things that can contribute to abdominal pain on running, ranging from the way you breath to your pre-run meal and your state of hydration. For more detailed information, the following are listed from very basic to more detailed information: http://bit.ly/15cyTsa http://mil-com.me/1DKhaHs http://bit.ly/1Cft6wp http://bit.ly/1BBHDoz.