Lower abdomen pain since last 7 months no symptoms only abdominal pain its mild but happen all day mu usg report is normal what it could be?

It is not feasible to provide a meaningful opinion without taking additional history, physical examination and may be some tests. It would be prudent to see your doctor and discuss if you may be depressed. Counter-intuitive as it may seem, exercise may help. Start with low intensity exercise such as walking and gradually increase the intensity as tolerated. Drink more water. Wish you good health!

There are too many diagnostic possibilities to answer your question is a meaningful way. It is not normal to have constant daily abdominal pain at your age and you should see your doctor and probably a gastroenterology specialist. It may be something as simple as constipation but your symptoms may have another treatable cause. The first step is to see a doctor for evaluation.