What you have described clearly is what is better known as
Gastro esophageal reflux disease. Reflux of gastric contents occurs due to a number of different causes, some of which are secondary to transient relaxations of the lower end of the
esophagus, a lax lower esophageal sphincter, a defect in the diapragm , a hiatal
hernia and so on.
patients suffering from reflux require long term therapy with
proton pump inhibitors in addition to the lifestyle changes you adopted earlier...but for patients who do not improve, further testing is warranted, including a pH monitoring.
Patients not responding to sequential medical therapy, may need to opt for interventions, some of which are endoscopic, or may be surgical. The purpose of these procedures is to strengthen the lower end of the esophagus, and prevent further episodes.
I suggest you make an appointment with a gastroenterologist and seek proper care.