You are suffering from Bromhidrosis. And Bromhidrosis can occur because of many reasons. Bacterial overgrowth (not Infection) is the most common reasons. It is treatable and thus you should visit a dermatologist because you will need to use prescription medication. Another reason for body odour is the foods that you eat. Pungent foods like onions, radish, garlic etc can also aggravate body odour. But that doesn't mean you stop eating them. Eat them in moderation and see if the odour comes under control. But definitely visit a dermatologist. You will benefit.
Thanks for the query.
This presentation can be seen with many skin diseases. The best option is to consult a Dermatologist in person to understand the problem and get it diagnosed. A proper treatment can then be started. Discuss the situation and hope it will be cleared in few days. You should check for trichorrhexis nodosa or any other skin disease affecting armpits with help of Dermatologist.