Yes. Most ulcers are induodenum not stomach; most are caused by bacterial infection with h. Pylori; some caused by meds like Aspirin and nsaids; rare other causes. Symptoms can come and go, esp in h pylori cases that are untreated (with antibiotics). Recurring symptoms need to be checked out to make sure something more serious (like cancer) isn't the cause.
Do higher amount of gas for a month & stomach pain around belly button for a week (gets relieved after motion) indicate stomach ulcer or liver tumor?
Neither. Try to alter your diet to see if that brings relief. If that does not help, you should consult a doctor for the stomach pain as that may be due H pylori infection. For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex.
There can be no. Symptoms to a constellation of ones ranging from stomach pain, aches, cramps, nausea, vomiting, fatigue related to blood loss, back pain, heartburn, bowel habit changes to changes in the stool to name a few.