Unfortunately many people who are disabled initially get denied by the Social Security Adminisitration.  It could be that Social Security did not get all of your medical records.  Sometimes even though your doctor may tell you that you are unable to work he or she will not write that in the medical reports.  Sometimes even if Social Security gets all the medical reports and your doctor says you are disabled you are still denied.  The most important thing you can do in this situation is not get discouraged or overwhelmed by the paperwork involved and appeal the denial.  Many cases are approved on appeal.