try chiropractic care. Usually very cheap and possibly could fix the problem. What I would recommend first is to get an insurance plan. You can get your own policy for relatively cheap. Once you have a diagnosis then everything will be a pre-existing condition. This can come about even from a trip to the emergency room. What I would recommend is try for a medicaid type insurance. Not sure what it is called in your state. if you do not qualify. try insure.com they can provide you a policy that would be effective upon first payment. As far as heat that may not help the back issue. Could possibly make it worse. Ice for 15 minutes on and off work the best. try some stretches. here is a site that will help with them

http://www.spine-health.com/wellness/exercise/overview-sciatica-exercises