Don't waste your time with a lawyer initially. There's nothing they can do at this level to help you. Go to www.ssa.gov and click on the link in the middle of the page that says "applying for disability". Just follow along from there. If you are seriously ill there should be no problem. If you do get denied the first time you just call the SS office and tell them you want to appeal. They have you fill out another form similar to the one you filled out the first time. A lawyer still can't help you at this round. If you are denied again, then it goes to a hearing before a judge. A lawyer may be able to help you at this stage, but is still not necessary. Don't give up a percentage of your money at the initial stages for nothing.
Litigation is any lawsuit or other resort to the courts to determine a legal question or matter. Litigation is essentially the name given to any lawsuits, no matter what their status. If an issue is currently in litigation, that means there is a lawsuit involving that issue. It may be just filed, in the middle of discovery regarding the suit, in the middle of arguments, or even sitting waiting for a finding by the judge, and it would still be referred to as litigation.