I Have Itchy Reddish Pink Bumps (look More Like Little

I have itchy reddish pink bumps (look more like little welts) up my sides, on my boobs and spreading to top of my pubic area. They are itchy at times. They aren't always as noticeable. What is it? I also have red bumps on the bottom of my butt cheeks kinda by the anus. Those don't itch. HELP.