I have brown spots that have spread between my breasts and underneath them as well. Never had this before until a few months ago. Please help!

Seborrheic Keratosis. A seborrheic keratosis usually appears as a brown, black or pale growth on the face, chest, shoulders or back. The growth has a waxy, scaly, slightly elevated appearance. Occasionally, it appears singly, but multiple growths are more common. Seborrheic keratoses don't become cancerous, but they can look like skin cancer.