I've been on disability since 96. Here are my suggestions. You need a doctor on your side. Try to avoid part time work if you can cause it can serve to lower your average for calculating the disability payment. Then start adding up all the things that are wrong with you. The more the better. You have a chronic disease, you must be depressed. Do you have high or low blood pressure?. Are you overweight? Are you sound and light sensitive? Anything else a Doctor will document?
Once you get a Dr to say that you can't work and it goes on your chart you are moving along. Then do the paperwork to apply. They will turn you down. APPEAL! Always APPEAL! When it gets down to seeing a judge say OK, set a date. Don't get a lawyer till you have a court date, they take a large portion of your check just when you probably need every penny.
I got my first check two days after I set a court date, I never got a lawyer. If you think the amount is too low, get it checked out. The amount you get will be the basis for your Social Security for the rest of your life, don't get cheated.
Once you get on checks they will hassle you every few years, just keep seeing your Dr. and reminding him of all the reasons you can't work. Keep getting it in the record.
If you don't have enough quarters for Disability you may qualify for other programs. If you aren't well enough to check into them get a friend or relative to do the leg work.
Good Luck - Cactus