I've a really bad pain in my left foot all the top part of my foot with a big vain sticking out when the pain is intense?

See a podiatrist: You need an evaluation to make sure there is not a fracture or ganglion and to see why you have the pain.

See a doctor: You need to determine where the pain is emanating from and if from a joint space this type of arthritis needs a specific diagnosis. If not, you may have anything from a tendon strain to a stress fracture, or a variety of other conditions. Go see your pcp. If they feel necessary they can refer you to a podiatrist. Good luck.

Venous insufficiency: You may have "leaking valves" in one or more of the long veins of the leg. These connect with the veins of the feet and can cause them to enlarge and become painful. The diagnosis is made with ultrasound and the vein can be usually treated with a laser through a small needle puncture.

Pain: Need to be evaluated to decide if this is vein related or foot related Often a inflammatory problem can cause swelling and then veins become more prominent