I don't have the same itch on the chest area as you are experiencing. But I had red rash and itch on my thigh and abdominal area. A awhile back I had the same rash and itch on the same areas. I had skin candida (yeast) infection on those areas.
MMS brought the rash and itch back for a few days. I think what happened is this: I had candida at those areas but dormant. Miracle-Mineral-Supplement killed candida and toxins released caused the itch and rash. It only lasted for about 3 days then it was totally gone.
I suggest you not to stop Miracle-Mineral-Supplement . Reduce the dosage if the rash and itch is too much to bear. They should go away soon.