left lung pain :: Article Creator Pain Under Left Breast: 10 Potential Causes And When To See A Doctor, According To Experts Feeling pain under your left breast can be especially worrying. After all, important organs and structures sit on that side of the body, like your heart, left lung, stomach, spleen, oesophagus, ribs, and more. So, what happens if suddenly, you feel pain in that area? Is it necessarily a cause for concern? First, don't panic. It's important to consider different factors before jumping to conclusions, says Dr Samantha Nazareth. For example, how old are you? What you were doing when the pain began? What is your pain severity? You should also consider what your medical history entails, what medications you're on, and if you have any other symptoms along with the pain, Dr Nazareth says. In some cases, pain under your left breast could be totally harmless, but other times, it might signal an underlying medical issu...