With any abdominal pain, it's best to see a physician especially when one has ruled off constipation, gas/bloating and other unserious symptoms as sometimes (and in rare cases) they might be pointers to serious internal issues.
Abdominal pains/stomach ache occur in different parts of the stomach and they are usually indicators of something going on within:
1. Tenderness at the right side on the lower part of the stomach is usually of appendicitis
2. Pain in the upper part of the stomach may be a sign of health issue with the pancreas: pancreatitis
3. Bloatness and pain in the centre of the stomach may be a sign menstrual cycle is around the corner (it's important to keep a calendar to know one's cycle).
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4. Pain around the stomach and late menstrual cycle (up to 10 weeks late) could be a sign of ectopic pregnancy which should be checked out without delay (It could be deadly).
5. Pain throughout the whole stomach could be a sign of perforated ulcer
With excruciating stomach pain that wont subside even after medications, best to have a physician check and immediate scans and relevant examinations done ASAP.