Underneath my armpit the side, i have a rash of spots, sometimes will get itchy. not sure if its when i shave, or my deodorant, or my clothes detergent. whats the best thing to soothe and get rid of these?

Itchy spots: More than likely these are irritated or allergy caused lesions by one or more of the possibilities you raised. A yeast infection is a less likely cause.Start with avoiding the use of the deodorant until lesions clear up & then change to another. A nonprescription strength corticosteroid ointment may help. Avoid tight fitting garments. See a dermatologist as needed if not improved.