Why do my ankles burn and my calves hurt when I walk more than 6blocks?

Extremity pain. What you describe may be symptoms of peripheral arterial disease. This is a reduction in blood flow thru the artery. When walking pain develops without knowing your medical history it is difficult to say for sure. Evaluation by your physician should be done as soon as possible.
Claudication? You may have intermittent claudication which is related to you blood flow to your legs. If your medical history has smoking or arterial disease, this could be a cause of this consistent pain when walking. See your doctor or find a specialist. I hope this helps.