Hi,
Welcome to the ehealthforum and I am really glad to help you out. There are many causes of shortness of breath which need to be ruled out in your case. It can be due to anemia, asthma like conditions, bronchitis, high blood pressure, diabetes, hypothyroidism or obesity.
Certain heart conditions too can cause breathlessness. In your case, smoking cigarettes can be one of causes of shortness of breath. It is advisable to stop smoking because it can cause not only dyspnea but is one of the leading causes of lung and oral cancer. The pain in the stomach area can be due to gastritis or gastroesophageal reflux disease( GERD) but it is important to rule out any cardiac cause as well.
Cardiac tests like ECG, stress echo and treadmill test, pulmonary function tests, blood tests, Hb Levels, thyroid hormones and CT chest need to be done to confirm the diagnosis. Please consult a physician and get these done. GERD is treated by antacids, bland diet, small evening meals and elevation of the head of the bed. If the symptosm persist then medicines like H2 blockers and PPI inhibitors like omeprazole , rabeproazole may be needed.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care.