Are you overweight? Perhaps it might be problems with your abdominal muscles(obliques?). One other thought just occured to me that if the problem is more towards the back, it might be a kidney issue. I am glad you are feeling better drinking more water. Sometimes when people are ill they may not drink enough water. If someone's body is quite toxic due to mercury or cndida, then they need more water intake to help eliminate toxins. Too much water though causes accelerated loss of minerals and water soluable vitamins, so one needs to find a reasonble balance.