Non itchy rash w/ little bumps on my chest! Help!

For a few months now I have had a rash of small white pustules all over my chest. At the top along my collar bones and right in the middle. I originally thought it was acne, but it's more rashy, but it does not itch. I have tried everything. I was putting hydrocortisone cream on it daily and it totally went away. I don't want to have to use something like that every day. I stopped using it and had a complete flare-up! I would like to know the underlying cause so that I can treat it and cure it. Please help! Thanks so much!