Ringworm is a fungal infection of the skin. One common way that we get it is from our pets, either cats of dogs. It is contagious and can be passed from one person to another either by contact with the infected person or contact with items of their clothing or personal care items. In other words, from their clothes, a hairbrush, a comb, or any other item. You can also pick it up from the soil when walking on it barefoot or handling dirt with your bare hands. And it isn't uncommon to pick it up in school lockerrooms and showers.
Ringworm needs to be treated with some form of anti-fungal medication. Some that are useful are: clotrimazole (Cruex cream, Desenex cream, Lotrimin cream, lotion, and solution), miconazole (Monistat-Derm cream), ketoconazole (Nizoral cream), econazole (Spectazole), naftifine (Naftin), and terbinafine (Lamisil cream and solution). Most of these are sold over-the-counter and will clear up the problem in about two weeks.
However, before you dive into self-treatment, I would recommend being seen by a physician and having a definitive diagosis made. That way you know that you are actually treating the problem that you have.