I've had the exact same symptoms as you for ten years now, come April 2008. It's driving me crazy and I, too, have had tests that indicate nothing wrong. I've had so many diagnoses - all of them wrong, I think. Fibromyalgia, poor circulation (circulation is just fine), scar tissue, stress. I think the one it might be is muscle imbalance. I'm doing a series of exercises taken from a book by Pete Egoscue. I have no inflammation, either, and really no pain. Just the odd feelings in my rear end, legs, and feet. I don't think it's MS, I think it's something more benign, but probably more irritating. Light exercise seems to help me, but vigorous exercise seems to irritate the whole thing. I'm just hoping I can find a cure before I hit the ten year mark. Good luck to you.
I agree with the workup thus far, including the EMG and lumbar plain film.
Further evaluation of the lumbar spine can be done with an MRI - which can evaluate for any nerve compression or herniated disk.
If MS is a concern, an MRI of the brain and spinal cord should be done, as well as a lumbar puncture.
Another neurology referral can be considered, preferably at a major academic medical center.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patients education only. Please see your personal physician for further evaluation of your individual case.
Kevin, M.D.
www.kevinmd.com