I believe I have a varicose vein in my calf and it keeps hurting. Any advice for pain relivers?

Ibuprofen. And warm compresses may help assuming it is a thrombosed varicosity. You should consult with a vascular surgeon to have it checked out and look into getting a venous duplex reflux study to rule out venous incompetence.
Naprosyn (naproxen) to start. Varicose veins can be quite painful. Basic treatment is compression stocking best put on upon arising, nsaids like naprosyn (naproxen) or Ibuprofen and elevation. More definitive treatment should be after evaluation with an ultrasound to determine cause and extent of problem and then treatment with a vein expert like a phlebologist.
Ibuprofen. The ideal treatment for varicose veins is a venous reflux exam to look for leaking valves which are the source of the varicose veins. Correcting the varicose veins with a laser closure procedure would be the treatment of choice. Ibuprofen would help to soothe vein pain but you should see vein specialist for a full venous evaluation and to see why your veins are hurting you.