They have never blistered or hurt
This isn't typical for any STD. If you are uncircumcised, probably it's just minor irritation or maybe a yeast infection. If it continues or you remain concerned, see a doctor. But I doubt it's anything important.
Could be many things. Does not sound like herpes to me as the bumps would have healed by now if it were herpes. Go to a doctor to have it evaluated.