I'm so sorry you got denied. Your chance for a positive outcome of your appeal is slim. 86% of reconsiderations are denied. Depending on how detailed your first application was you could file yourslef with a great deal more detail and medical records. The reconsideration is based on new information since the date of your application or anything that wasn't included. I would contact the Socials Security Administration and ask for a copy of your file. It will have more information about why you were denied than your denial letter.
If you get an attorney thoroughly vet them, know their rate of success at each appeal level.