My right calf and foot feels colder inside than the other. cramping in calf bum and pain in lower back. both feet seem to look and feel the same.worry?

Be seen: I would be seen. The two most common causes are a sciatica, or some form of vascular problem. A sciatica is an irritation if a nerve in the back causing symptoms in the leg and is usually not dangerous; but if you are having done form if arterial insufficiency into your leg it could be limb threatening. A simple exam can determine the likely cause.