Hi & Welcome. Non-radiating sharp chest pain on the left side of the breast could be due to Costochondritis (inflammation of the cartilage that connects a rib to the breastbone or sternum). Usually the pain goes away on its own. However, you can take non-steroidal anti-inflammatory drugs such as Ibuprofen or Naproxen which are available over the counter. If the pain does not subside consult a GP for proper clinical examination and certain lab tests such as chest x-ray & ECG to rule out other conditions like heart disease, lung disease, gastrointestinal problems or osteoarthritis Hope you would find this advice in getting the remedy for your problem.