Ringworm is a type of fungal infection that commonly occurs. It is a infection of the skin that is readily treated and rarely progresses to cause major problems. That being said, it requires medical attention. I would recommend that you see your doctor
in order to have this addressed.
Ringworm, or tinea, is a fungal infection of the skin. This is in the same family as jock itch or even athlete's foot. It can be caused by poor hygiene -- or moist and warm skin as this allows the fungus to grow. The infection is limited to the skin and rarely progresses. Without treatment, and simply maintaining good hygiene, it is possible this will heal itself over time. However, this can be readily treated with application of an over the counter anti-fungal cream (any over the counter miconazole or terbinafine [ Lamasil] will work). You do not need a prescription for these creams. Talk to your local pharmacist as he or she can point you in the right direction.
That being said, I would still see a doctor. The chest is an uncommon spot for this and I would be concerned there is another cause of your skin condition. Bacterial infections can look similar and can readily cause life threatening illnesses without treatment.