I have some small bumps on my chest and torso. They are about half a centimetres in diameter, have been present for more than a year. They are not movable and more than 10 of them are present in different part of chest and belly. There is no pain and seems to be slow growing and have a slight dark colour under the skin. I have visited some doctors but they can not get to any conclusions. Are there any chance of them being cancerous?