hi,taking your symptoms into account it seems you are suffering with one of the following-
1.most probably it could be peptic ulcer
.it occurs due degradation of protective mucus layer with acid.
2.it could be chronic pancreatitis
, especially if you are an alcoholic.
3.it could be what we call "mesenteric insufficiency" which is similar to coronary insufficiency where transient ischaemia occurs due insufficient blood supply to intestines when demand increases.
4.lastly and most dangerous of all it could be gastric carcinoma.
Try having pantaprazole tablets.If it relieves symptoms then peptic ulcer can almost be confirmed. and don't forget to see a gastroenterologist later! hope it helps. take care! :)