Hello!
Thank you for the query.
It would be easier to answer your question, knowing what tests has been performed. It is impossible to recognize 
gastric reflux disease without endoscopy. 
Such pain may be caused by heart problems, gastric problems and lungs problem. And this diseases may be concomitant. 
So you should have: ECG and blood work for troponine and CK-MB (necrosis heart enzymes) and heart ultrasound may be necessary.
Endoscopy should be performed as 
acid reflux may be not a disease itself, but a symptom of 
peptic ulcer, 
hiatus hernia and other gastric diseases.  During the endoscopy there should be performed test for 
Helicobacter Pylori. If it will be positive, antibiotics and 
proton pump inhibitors therapy is necessary. Reflux disease may be diagnosed with esophageal ph monitoring. Abdomen ultrasound should be performed as well and fool blood work with liver and pancreas enzymes to rule any other upper digestive tract diseases.
Such pain may be also caused by either asthma or COPD (chronic 
obstructive pulmonary disease - this one is associated with smoking). Moreover, acid reflux is very often related with asthma. Chest X-ray and spirometry should be performed.
Your acid reflux (when recognized) may not response for your current treatment, and some other acid blocking medicines might be necessary.
Hope this will help.
Regards