Once you get yourself comfortable and pain free, I'd personally start with just walking (gradually extending how far you go; according to what works for you) & try doing the gym with a personal trainer (or physical therapy) for further exercise routines. Going to a chiropractor, massage therapy or even acupuncture may also be helpful before you start working out. With that much pain going on, I definitely wouldn't push it. You need to get yourself pain free, comfortable and confident in movement, so you don't injure yourself.
Sorry, if I am not much help.