First thing is relax, and don't worry about your situation. Your symptoms are not suggesting any major disease.
Most common reason can be:
1. You may have mild colitis or typhlitis
2. You may have umbilical/periumbilical hernia in making.
3. IBS due to stress or other factors.
Slight more information and clinical examination will give a better idea.
Next Steps
next step is
improve your diet, take light healthy and high fiber diet with easily available probiotics
keep a watch on associated features with pain
try to relax , ask your loved ones that whether they feel any change in your mood and behaviour which is abnormal.
Health Tips
relax and try to improve upon your life style.
and
have consultation if symptoms persists or increase in pain.