Why is my Social Security application taking so long?
It can take the SSA about six weeks to process your application and start your benefits. However, it might take longer if you supply incorrect information, or the SSA requests that you provide additional information to process your case.
In this regard, How do I check my disability back pay?
Call the national Social Security Administration’s toll-free number, 1-800-772-1213, to receive information about your retroactive payment. The line is open 24 hours a day for you to find out your claim status and if your back payment has been processed.