Brief Answer:
Possible COMPRESSIVE NEUROPATHY vs. metabolic or central defects

Detailed Answer:
Good afternoon,

Your symptoms are consistent with some type of sensory phenomenon in only one leg (the left) which could be happening because of excess compression upon the nerve roots that provide sensation below the knee (usually the L4 root...or L5 if the foot is also involved). I would therefore, wish to order an MRI of the lower back on you to see what the lumbar spine looks like and if there were a bulging, herniated, or otherwise architecturally compromised spinal column at the L4/L5 disc level. I would also get an MRI of the brain (with gadolinium contrast) if the lumbar spine were clean looking for any abnormality in the RIGHT HEMISPHERE close to the top of the frontal convexity of the brain. We would want to look there for any abnormalities that could be telltale of your symptoms as well.

At the same time I would also order bloodwork on you to make your thyroid, Vit. D, and Vit. B12 and folate serum levels were all normal since deficiencies in these metabolic elements could also give you the "start" of a neuropathy as you describe. Incidentally, numbers that we tend to look for as being sufficient to be considered "good to go" would be at least 400 for B12, Vit. D- 60-80, and thyroid (get FT4 and TSH) numbers according to lab values.

Finally, for the detail that your symptoms are ONLY or MOSTLY at nighttime when you are ready to fall asleep, one could consider the beginnings of the condition known as RLS although the oddity of this case is that you are only complaining of 1 leg being involved and not both which is the most likely scenario for RESTLESS LEGS SYNDROME.

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