RATIONALE: 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. 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. It is not yet known whether giving gemcitabine together with sorafenib is more effective than giving gemcitabine alone in treating pancreatic cancer.