What Causes Numbness On Finger Tips?

Hi, the tips of my middle fingers get numb throughout the day, at times I have to pull them to get sensation back cause they turn white, cold and numb( doesn't matter if I'm cold or not.) Also feel electroshocks if I grasp my hands together. I do get alot of headaches.I do work at a rock quarry outdoors(shoveling). Hired on as a truck driver but it has been raining a lot,
Studied to become a Medical Administrative Assistant, this is how I know about this site...Insurance barely kicked in and I have to drive about 50 miles to see doctor. Beforehand...thank you