Help please? what is causing the burning sensation in my left breast ?

Radiculopathy: It is possible that the pain could represent irritation to a nerve root in the spine causing radiating pain to the breast. If the pain is accompanied by a rash in the area, it may be a case of shingles. It is also possible to have pain from trauma to the area. A physical exam and more detailed history would help in sorting through the various possible causes.