What Causes Itchy Rashes On Upper Back And Shoulder?

i have a itchy pimple like rash only on my upper back and shoulders. The bumps go away an hour after i take a shower but appear later in the day. The problem gets worse if i skip a shower. I have switch to non-scented soaps but still have the problem. I have no insurance so seeing a Dermatologist will be hard. If you can please try to tell me what this might be and how can i treat it. Thank you for your time.