What causes persistent (several months) burning l mid abd pain migrating to l mid back area even though I completed an h pylori treatment?

Ulcer treatment pain. Although the burning is most suggestive of an ulcer there are a variety of potential other causes including splenic or pancreatic sources. It is most likely related to the ulcer and the very first thing to do is schedule a follow up endoscopy to ensure a satsifactory response to the h. Pylori. You may not have had a complete response and may require a second round of antibiotics.