 This randomized phase II is studying how well giving sorafenib with or without gemcitabine works in treating patients with metastatic pancreatic cancer. Sorafenib may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth and by blocking blood flow to the tumor. Drugs used in chemotherapy, such as gemcitabine, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Giving sorafenib together with gemcitabine may kill more tumor cells. 