Pain under your left ribs can come from several different organs and structures packed into that area of your body, including the spleen, stomach, part of the pancreas, a section of the colon, the left kidney, and even the heart and left lung sitting just above. The cause ranges from something as minor as trapped gas to something as serious as a heart attack, so the specific quality of your pain, how it started, and what other symptoms you have all matter.
What’s Actually Under Your Left Ribs
Your left upper abdomen houses more anatomy than most people realize. The spleen sits tucked against the lower ribs on the left side. The stomach curves across the upper abdomen, with a large portion on the left. The tail of the pancreas extends to the left, and the left kidney sits behind everything else, closer to your back. A sharp bend in the colon called the splenic flexure also lives in this space, right where the colon turns downward.
Just above the diaphragm, the lower lobe of the left lung and the heart sit in the chest cavity. Problems in either can produce pain that feels like it’s coming from under the ribs rather than inside the chest.
Trapped Gas in the Colon
One of the most common and least dangerous causes is splenic flexure syndrome. The splenic flexure is a tight bend in your colon where it turns sharply beneath the left ribs. Gas moving through your digestive tract can get stuck at this curve, stretching the colon wall and causing a cramping or pressure-like pain that feels surprisingly intense. Think of water rushing toward a sharp bend in a river: too much volume overwhelms the turn. Some people are born with an unusually tight curve in this area, making them more prone to the problem. The pain typically eases once the gas passes, and it tends to come and go rather than staying constant.
Stomach Irritation and Gastritis
Because the stomach sits mostly on the left side of your upper abdomen, inflammation of the stomach lining (gastritis) or an ulcer can cause a gnawing or burning pain under the left ribs. This pain often gets worse after eating, and you may notice a feeling of uncomfortable fullness in the upper belly even after a small meal. Gastritis can be triggered by overuse of anti-inflammatory painkillers, heavy alcohol use, or a bacterial infection in the stomach lining. If the pain is a dull burn that flares with meals, your stomach is a likely suspect.
Spleen Enlargement
The spleen normally sits quietly behind your lower left ribs, but when it swells, it can press against surrounding structures and cause a distinct pain or fullness in the left upper belly. That pain sometimes radiates up to the left shoulder, which catches people off guard. An enlarged spleen can also press on the stomach, making you feel full after eating very little.
Many different conditions can cause the spleen to swell. Viral infections like mononucleosis are among the most common triggers in younger adults. Liver disease, certain blood cancers, autoimmune conditions like lupus, and blood clots in the veins near the spleen can also be responsible. If the pain gets worse when you take a deep breath, that’s a classic sign of spleen involvement.
Pancreatitis
The tail of the pancreas extends to the left side, so inflammation of the pancreas can produce pain that centers in the upper belly and radiates to the back or shoulders. In acute pancreatitis, the pain is usually severe, comes on suddenly, and gets worse after eating. Chronic pancreatitis causes a more constant upper belly pain that also tends to flare with meals. Heavy alcohol use and gallstones are the two most common causes. This type of pain is hard to get comfortable with. People often describe it as boring straight through to the back.
Kidney Stones or Infection
Your left kidney sits behind the other organs, closer to your back and tucked under the lower ribs. A kidney stone lodged in the left kidney or ureter can cause pain that wraps from the back around to the side, sometimes felt under the ribs. The pain often shifts location or intensity as the stone moves. Kidney stone pain is notorious for being severe and coming in waves.
Other clues that point to a kidney problem include cloudy or foul-smelling urine, a constant urge to urinate, nausea, vomiting, and fever or chills if an infection has developed. Blood in the urine is another telltale sign.
Rib and Cartilage Inflammation
Not all pain under the left ribs comes from internal organs. Costochondritis, an inflammation of the cartilage connecting your ribs to the breastbone, produces a sharp or aching pain that often affects the left side of the chest. It can radiate to the arms and shoulders and gets worse with deep breathing, coughing, sneezing, or any twisting movement of the upper body. The pain can feel alarming because it mimics what people imagine a heart problem feels like, but pressing on the tender spot along the breastbone usually reproduces the pain, which organ-related causes won’t do. Costochondritis is typically caused by physical strain, repetitive movements, or a respiratory infection that led to heavy coughing.
Heart and Lung Causes
Pain under the left ribs can sometimes originate in the chest rather than the abdomen. Heart attacks don’t always feel like dramatic chest-clutching pain. They can present as severe nausea or pain in the upper abdomen under the rib cage, especially in women and older adults.
Pericarditis, an inflammation of the sac surrounding the heart, causes sharp chest pain that can be felt under the left ribs, along with palpitations and sometimes fever. A blood clot in the left lung can also produce left-sided rib pain and may quietly lower your oxygen levels even before you notice shortness of breath. Pleurisy, where the tissue lining the lungs becomes inflamed, creates a sharp pain that worsens with each breath and is often felt along the lower rib cage.
How to Tell What’s Serious
The character of your pain offers important clues. Crampy pain that comes and goes, especially with bloating, is more likely gas or a digestive issue. A burning pain tied to meals points toward stomach inflammation. Sharp pain that worsens with breathing or movement could be musculoskeletal, or it could involve the spleen, lungs, or heart lining.
Certain symptoms alongside the pain signal that you need emergency care rather than a wait-and-see approach:
- Severe pain that makes it difficult to move, eat, or drink
- Sudden onset of intense pain that wasn’t there minutes ago
- High fever
- Blood in your stool or vomit
- Pain after abdominal trauma from an accident or injury
- Chest tightness, jaw pain, or arm pain suggesting a cardiac event
For persistent left upper quadrant pain that doesn’t resolve on its own, a CT scan with contrast is the imaging study most commonly used to identify the source. An abdominal ultrasound is another first-line option, particularly when spleen enlargement is suspected. In many cases, one of these two tests will reveal the cause.