I suffer from chronic pain from the waist down in both legs that get so bad it shoots up my back. what could be the problem?

Low Back Pain: It would appear that you have lumbosacral disc pathology with some compression of the nerves that go down your legs. You will require a lumbosacral X Ray and MRI to determine the exact pathology. Since you have indicated that this is a chronic condition, it would be good to consider an epidural injection if indicated, to help relieve the symptoms of pain in your legs. No strenuous activity please