Hello dear, thanks for your question on HCM. 
Since your extensive cardiac work up is normal, no need to worry for cardiac cause. 
In my opinion you are having GERD ( 
gastroesophageal reflux disease ). 
It is due to laxity of gastroesophageal sphincter. 
Because of this the acid of the stomach tends to come up in the 
esophagus and cause the symptoms. 
Along with antacids, you need to follow these lifestyle modifications for better symptomatic relief. 
1. Avoid hot and spicy food. 
2. Avoid 
stress and tension. 
3. Avoid large meals, instead take frequent small meals. 
4. Go for walk after meals. 
5. Keep 2 - 3 pillows under head in bed to prevent reflux. 
6. Avoid alcohol and 
smoking if you have these habits. 
7. Loose weight if you are 
obese. 
Don't worry, you will be alright.