First make sure that you do not have a magnesium deficiency because this can cause calf pain. You may also have referred calf pain if you have entrapment of sacral nerves at the level of S1 and S2. There are vascular concerns if you have calf pain with walking. It is called intermittent claudication and may be a problem with people who have vascular disease and trouble with atherosclerosis. It may get better with rest. But if it happens even with rest the blockage of the blood flow would be more serious. This can get worse if you are a smoker because this further constricts blood flow. It might be wise to see a vascular doc to do doppler studies to evaluate pulses and signs of decreased blood flow. If you suspect it is more likely a back issue a orthopod or neurosurgeon is your best bet.