Lydia:
It sounds to me as though you are describing the viral condition called molluscum contagiosum. This is an unfortunate name, because these harmless viral bumps are really not contagious from one person to another. Kids often get them in various places such as the chest or neck. They sometimes get a little bit red, but they always go way even if left untreated. The average duration is a little on the long side, though, about nine months.
Because most treatments involve pain and multiple sessions, I usually advise parents of young children will have them to just let them be until they disappear on their own.
Good luck.
Dr. R
ASR