You definitely should consult a vascular specialist. It does not appear, based on my limited reading, to be your usual varicose vein. Plus the WrongDiagnosis site below lists many different causes for vein pain. If this vein is effecting your life to the extent you say it is then it sounds like its time to see a specialist and see if you can get it cleared up.
Good Luck!
http://www.wrongdiagnosis.com/sym/vein_pain.htm