The most obvious cause is a rib cage injury of some sort. Broken, bruised, or fractured ribs may cause varying degrees of pain depending on their severity and cause. In addition, a pulled or strained muscle may contribute to muscle pain below your rib cage.
In severe injuries, there may also be an injury to the underlying organs, inflammation in the lungs, diaphragm injury, muscle spasms, or a problem with the rib cartilage. The gallbladder and kidneys also lie below the ribs – which is why it’s important to get any rib or rib cage pain checked out.
Further, in certain conditions – such as fibromyalgia – widespread pain or trigger points aren’t uncommon. For other types of side pain, check out our article here.