As many as 20 million Americans suffer from pain caused by gallstones, which form when there is a chemical imbalance in the gallbladder. Though health care providers are not exactly sure why some people develop gallstones and others do not, there are a number of causes including obesity, pregnancy, a high-fat diet and family history, to name a few. While some people may experience no symptoms of gallstones, when the gallstone inflames the gallbladder it can be very painful and even lead to infection.