Stomach pain may not necessarily be stomach cancer, and three months is a long time. If the patient continues to have stomach pain for such a long time, it is not completely sure that it is stomach cancer. In this case, gastroscopy is recommended because it is one of the most important means to detect gastric cancer. Under direct vision gastroscopy, it can clearly find out whether the patient has peptic ulcer, occupying lesion of stomach or simple chronic gastritis. At the same time, pathological examination can be performed for inflammation and ulcers of unknown nature, and the nature of gastric disease can be further analyzed by pathological laboratory tests. Therefore, it is not possible to judge whether there is stomach cancer simply based on stomach pain. Three months is a long period of time, and if the patient continues to have pain within three months and still cannot be relieved after taking medication, it is also strongly recommended that the patient must come to the hospital for corresponding gastroscopy, combined with abdominal CT or B-ultrasound to determine what causes stomach pain lasting for three months.