Hi, I am an American Board Certified Neurologist and I am very glad to help you with your health concerns.
There are few neurological conditions that can cause the type of symptoms you are having. This could be pinched spinal nerves coming from the spine. Or this could be a type of neuropathy, especially small fiber type neuropathies can cause lot of pain. This also could be due to circulation problem causing reduced blood supply and resulting in pain. I am not sure how far you have been investigated, if not already done then you need an MRI scan of the spine, an EMG/Nerve conduction test which is a nerve test, tests for small fiber neuropathy (which may include a special type of skin biopsy), and tests to check the circulation to the legs etc and once the exact cause for your symptoms is identified it will be treated appropriately. In the meantime for the symptomatic relief from this severe pain you may try one or more of the following treatments;
1) Nerve-pain pills like Gabapentin or Amitriptyline
2) Nervex neuropathy pain relief cream
3) TENS (Transcutaneous Electrical Nerve Stimulation)
4) Calmare Scrambler Pain therapy
5) Evening Primrose oil
6) Capsaicin skin cream
7) Laser therapy (Cold laser type)
8) Lidocaine anesthetic pain relieving skin patches
9) Opioid pain killers (narcotic pain killers) like Lortab or Oxycontin
10) Complementary and Alternative medicine treatments like Acupuncture etc
I am not telling all these above treatments are required in your case; I am just providing you with a list of different treatment options that are available for the control of severe painful symptoms you are having. And if you see any of the treatments mentioned in the above list you have already tried then please disregard them, and you may consider trying the other options which you have not already tried.
Along with one or more of the above mentioned treatments you may also consider trying nutritional supplements like Metanx (a special combination of active vitamin b12, folate & vitamin b6), ALA (Alpha Lipoic Acid) & Acetyl Carnitine etc and these supplements may help in nerve repair & nerve regeneration (if you indeed have nerve damage) and this can additionally help in the relief from this severe torturesome pain.
Please let me know if you have any further questions; and if you feel you have received the answer to your question please rate me so that I can receive credit for the time and effort put by me in answering your question.