About two weeks ago I got really sharp pains at the top of my penis when I got home I checked it out and there was a black spot very very small. I went tot the doctors and told him about and he had alok he said it was nothing and that it would go away. I have noticed I only get the pain when my penis gets cold other than that there is no pain please help as my doctors is on holiday and I am worried :)

It sounds like something harmless like a Fordyce spot*, which is a form of misplaced hair gland. When it appears on the head of the penis, it is referred to as "Tyson's Glands".

Since the first recommendation in situations like this is to see a Doctor for a checkup, and you already have with a clean bill of health, then I would say it is time to relax a little.

*: Link contains medical images of male genitalia.