Hi, welcome to our site. I am Dr Saumya Mittal, MD. Read your query. That is a very significant question and i appreciate your problem. I will try my best to answer your query In case you ever have a left sided chest pain, or left shoulder pain, the first thing that anyone would tell you would probably be - Oh My God ! You probably have a heart disease. Yes, a cardiac issue is always considered first, because it is the most drastic possibility that can possibly be fatal. Once the cardiac issue is ruled out, often with extensive testing, your cardiologist will probably say, you are fine. Go Home . So what happened? is what you may ask. Here are 5 possibilities that may explain what may have happened- 1. Cervical spondylitis- The pain in the left arm in such patients is because of the compression of the nerves. Nerves in the body derive chiefly from the spinal cord. These may be getting compressed if there is some skeletal compression of the nerves. And this may be resulting into the pain that usually radiates from the neck, and down to the arm, or other parts simulating the heart conditions. Most doctors suggest an x ray of the neck, preferably an MRI spine. 2. Muscle strain- the muscles are all attached to the bones. So when you have left arm pain, it may be possible that there is an inherent muscle trauma that may be causing pain. Alternatively, the attachments of the muscles to the bone may be weak or traumatized and may therefore lead to pain as well. An NCV or EMG may help diagnose this 3. Gastritis. The nerve supple to the heart and the stomach is the same. And this also supplies the left arm. So when you have severe gastritis, the nerve takes the signal to the brain. Now since the brain receives signals from all three portions, it misreads the signals as pain in those parts. And thus we feel pain in left arm. Medically, this is known as referred pain. An endoscopy may help diagnose this 4. It may be due to some pleuritis. In fact the sharp shooting/stabbing pain in chest on breathing in is typical to pleuritis. Pleura are the covering of lungs. Now lungs per se do not feel any pain. But pleura do. So any infection or inflammation involving the pleura may cause pain. Accordingly, the pleural pain may be due to chest (lung) involvement or due to the covering. An x ray chest or ct chest may help 5. Rarely, an abdominal pathology, like tuberculosis of abdomen irritates the diaphragm. Diaphragm is a muscle between the chest and abdomen that helps control the breathing. When this is inflamed, there may be more pain too- again by referred pain. An ultrasound or abdominal MRI may help These are the posibilities that may cause left chest pain or left arm pain if it is not a heart condition. I will suggest meeting a good physician. they will be able to evaluate it properly to give you appropriate treatment. You may also try medicines like proton pump inhibitors before meeting this doctor. Now these medicines like esomeprazole are taken once daily- in your case I would suggest taking them just 1/2 hour before breakfast. They are quite safe and devoid of major side effects. So try a course of them. If it helps, your treatment is the same, and your diagnosis is confirmed as well. I hope this helps you. Inform the reports mentioned above/if any other so I can be of help further. I have given you the answer to the maximum considering the information provided. The results of the tests could further enhance my answer to you. Please do understand that some details could be extracted from a detailed history and examination. Please feel free to ask another query. I would be glad to help you. Looking forward to your return query with the details asked so that I can help you further. (If the answer has helped you, please indicate this) Best of luck. Dr Mittal. MBBS, MD (Internal Medicine), CC (Diabetes Mellitus), DNB (Neurology) Consultant Physician and Diabetologist JS Hospital Ex Apollo Hospital, Delhi Ex Kailash Hospital, Noida