These symptoms are concerning. I recommend returning to your primary care physician
to have this evaluated. There are many possible causes of these symptoms, some of which are concerning and some of which are less so. Regardless, this warrants an evaluation.
Chest pain is always concerning as we worry
about the pain coming from the heart. Normally heart pain is on the left or center of the chest, is a pressure like sensation and lasts minutes. It would be unlikely for a young person like yourself to have heart trouble, but not impossible. Certainly stopping smoking will limit your risk. The best advice in that regard would be to STOP SMOKING.
Smoking can also worsen abnormal heart rhythms, known as an arrhythmia. Common arrhythmias such as atrial fibrillation can give the sensation of your heart beating out of your chest or palpitations. This should be evaluated for.
There are many other causes. Pain after eating can be related to the gallbladder, especially after fatty meals. Gallstones can be evaluated for by an ultrasound. Reflux or heartburn is also a common cause, which alcohol and smoking both worsen.
See your doctor
for an evaluation. There are many causes, some serious, which should be ruled out.