What Causes Severe Pain In Calves, Heels And Arch Of Feet?

Hello.......I HAVE SEVERE PAIN IN MY CALVES ,MY HEELS AND ARCH OF MY FEET.IT MAKES IT HARD TO WALK WHEN I FIRST STAND UP,THE PAIN DOES NOT LESSEN MUCH, BUT IT DOES BECOMES MORE TOLERABLE AS I GO.WHAT IS CAUSING THIS,OR WHAT CAN I DO TO EASE THE PAIN?I ALSO GET LEG CRAMPS AT NIGHT.