Hey dr ,i have a pain in my stomach the moment i eat i feel am full already,what can i do doctor.thanks?

For almost any health concern, the first step is to have a healthcare professional do a good history and physical exam. Many causes can be determined in this fashion. Without additional information, the first things c=that come to mind are things like reflux disease (often abbreviated GERD), gastritis and ulcers. Pain and fullness, along with easy belching often go with reflux disease

It is not feasible to provide a meaningful opinion without additional history, physical examination and may be some tests. If you have lost weight It would be prudent to see a doctor, preferably a GI specialist. Wish you good health!