You have the right to appeal the decision. Always appeal the decision if your claim is denied through the framework provided by the government. Appeals escalate your case through different stages of examination, with the final appeal taking place before an Administrative Law Judge, where you are able to directly speak with the Judge about your medical condition.
It is important to note that appeals are time sensitive. You have 60 days from the date of the rejection, as stipulated on the notice supplied by the Social Security Administration, to appeal the decision.