Hi, welcome to the forum, your symptoms are suggestive of irritant dermatitis or urticaria. It seems secondary to the garments and sweating will worsen the condition. Bra may be responsible for such reactions.
Firstly, you need to get investigated for possibility of allergen (due to clothes, dye or other allergen where you work).
- White petrolatum or Zinc oxide cream can be used which acts as protective barrier.
- Low potency topical glucocorticoids and oral anti histaminic against prescription can be helpful.
I suggest you to consult dermatologist. Take care and regards.
What Laundry detergent are you using? Keep the receipt and return the bra's to the store immediately, requesting a refund. Make a note of the materials that these products are made of, as their is likely a man-made fiber that could be an irritant. Wear only cotton under-garments, that is always the best solution.