Hello i have pain in the bottom of my rib cage from the muscle at the bottom of the sternum to the left along the rib and the right.what is it?

Costochondritis: Also known as chest wall pain, is a benign and often temporary inflammation of the costal cartilage, which connects each rib to the sternum at the costosternal joint, and is a common cause of chest pain. Though costochondritis is often self-limited, it can be a recurring condition that can appear to have little or no signs of onset. Treatment options are quite limited and usually, rest, analgesics.