I seem to have a rash that moves to different parts of my body. usually under arm, or in groin area, and sometimes a red line near it.?

Moving rash: The armpit and groin are naturally moist, but also normally home to benign yeast, fungi and bacteria. This may be nothing to be worried about, but it can be a sign of diabetes. Diabetics are prone to infections. Other immune suppressors can also do this, so time for a check at a primary care provider more then a simple answer on line. Check it out to be safe.

Diagnosis?: This rash would likely need to be examined and more history obtained to be able to provide you with useful input about the diagnosis or possible treatment.