Lower abdominal pain at night

Patient: Hello, I had to wake up in the middle of the night today due to cramp like pain in the lower right of my abdomen (just to the side of the bellybutton). The pain is dull and is similar to the one we get after walking or running sometimes. Just this one does not go away. What can it be? This is the second time it happened in the last month and never before. Otherwise totaly healthy male of 29 years and 65kg to 1.82m