what could be causing intermittent pulsing left foot pain, outside of the ankle bone

I had this a couple of times ... For me it was related to a muscle spasms in the foot. They call it fasciculation and it can occur when a muscle is somehow overworked or pulled. In my case the nerve in this part of the foot was pinched during a long walk and my podiatrist told me that was actually the issue that make my foot buzzing. The podiatrist also suggested to add more salt into my nutrition.

I went to physiotherapist and a week of foot massage helped. He suggested to apply heat patches and I did it a couple of times. I also introduced more potassium in my meals. Eat bananas every day and drink potassium mineralized water.

Hope this helps ...