Pins and needles in heels of feet when lying on back with knees in air. also when sitting on any surface. or bending forward. where to begin looking?

Diet and exercise: You may take a multivitamin supplement, just in case it is due to nutritional deficiency. Counter-intuitive as it may seem, exercise may help. Start with low intensity exercise such as walking and gradually increase the intensity as tolerated. Have a healthy diet, exercise 30 minutes/day, drink plenty of water, have safe sex, no tobacco alcohol weed or street drugs.