What Causes Pain And Swelling On Thump?

Hi, I woke up through the night with a very sore thumb, I did some research and guessed it was athritis, I took Voltarin and this eased the pain alot over 24 hours. I woke this morning to find a raised vein on the first nuckle of my thumb (one closest to the wrist). this is where I felt was the main source of the pain which during those first painful hours seemed to be all around the knuckle area and into the wrist. Is the vein possibly clotted? should I go to a doctor. 40 year old male.174 cm 95 kg?