Your symptoms of upper abdominal pain just below the breast bone, belching, heartburn (burning pain behind your breast bone), general discomfort in the abdomen, feeling of constant hunger, bloating or fullness after eating, feeling sick, vomiting, are all due to peptic ulcer (duodenal or stomach ulcer).
The fact that you still experience the peptic ulcer symptoms and history of uncompleted treatment you were given, are suggestive for not healed peptic ulcer.
Back pain can be due to obesity and also your stomach pain due to ulcer can radiates to the back.
The nasty liquid you feel at the back of your throat is due to acid reflux.
As a result of being overweight and smoking cigarettes, you are most likely to experience symptoms of acid reflux or GERD, that are similar to peptic ulcer symptoms and adds to your problem.
First you should be evaluated about the condition of your peptic ulcer, since losing appetite is a sign that you may develop some complications.
If you are diagnosed with ulcer again, try to complete your drug treatment.
At the same time try to lose some weight, stop smoking cigarettes, eat healthy food, to ease the symptoms of acid reflux.
Best wishes!
Marija