I have to wonder if you take statins for cholesterol?

Have you had a blood test for CPK levels?
Abdominal ultrasound to examine for aortic aneurysm?
Cramping from walking suggests PAD or some circulation problem.

Tests for dermatomyositis or polymyositis? This typically starts in the hips/thighs.

I'd consider trying d-ribose. This is a powder that is a 5 carbon sugar, that jumpstarts your mitochondria and gives energy to the muscles.

Here is my ribose thread:
http://neurotalk.psychcentral.com/post708792-40.html

This may be very expensive in stores, but online it is a bit less $$

iherb.com and
Puritan's is where we buy ours.

Also for muscles would be magnesium, that is already mentioned.
You might find the topical lotion that you rub in more effective for certain areas. This is available now (newly) at WalMart...called Morton Epsom lotion. (in the first aid section).

If the ribose helps you, then consider the other supplements for the mitochondria which are:
acetyl carnitine
CoQ-10
R-lipoic acid.

It is not common for typical PN to affect hips first. Usually it appears in the extremities of hands and feet first.