It sounds like it could be Thrush if the bumps are really tiny. I only started get thrush after the first time I had unprotected sex, although apparently it's not necessarily passed by sex. it's a fungal yeast infection. It's really, really common so don't too scared, you can get cream and an oral pill from the chemist.
Normal Soaps can irritate it, try using a feminine hygiene soap down there. If you are sleeping with the same partner regularly you could be passing it back and forth between you. although men don't show any symptoms usually, they can pass it on and can get infections from it so ask him to take the oral pill too. Also if your man clips his pubic hair the stubble can irritate and make it come up.
I found that once I had it, it would flair up every now and then for no reason, particularly when I had my period and when I ate too much sugar or drank too much beer. also, weirdly, when I used condoms although that's no longer a problem as I'm in relationship and on the pill!
I hope that's what it is, good luck.