Why does mechanical allodynia cause pins and needles and pain down my legs, also i can't sit on my left buttock as the pain gets worst.

Neurologist: Allodynia is an unusual condition. I recommend an evaluation by a neurologist. Pins and needles sensation may be due to a deficiency of calcium, magnesium or potassium or can be a demyelinating process like multiple sclerosis. Sensory neuritis is another possibility and. there may be an inflammation of the sciatic nerve as evidenced by pressure on the buttock resulting in increased pain.