Hello, my name is Dr Helen and I hope I can help you.
It is certainly possible that these are simply small moles. Moles can appear anywhere on the body and you can get new ones any time. The fact that they are pigmented would suggest they are moles.
However there is a possibility that these are small warts caused by the human papilloma virus. HPV is a viral infection passed on by sexual contact. Usually though the HPV causes lesions which are flesh coloured, not pigmented, which does not fit with your description. However they do occur in little groups.
Here is a link that tells you more about HPV:
To get an accurate diagnosis you really need to have these examined either by your GP or you could go to your local sexual health clinic (held in your nearest hospital) if you would prefer.
These do not sound sinister but I think it would be helpful for you to be examined so that you can be given a definitive diagnosis.
I joined JustAnswer in June 2013 and am a UK doctor. I have been qualified for 23 years and have widespread experience in GP and cancer care.