Abdomina pain is a very broad subject- with no additional symptoms and normal bowel patterns, sounds like a muscle sprain/cramp/tear. I would keep an eye on it and if you start developing symptoms such as nasuea, vommiting, fever, or changes in bowel habits, I would make an appointment with you doctor
Thank you very much.
And also, these slight hardness and pain can be felt with my fingers even more when I lie down completely flat on the bed or floor. The pain is a bit sharp and it seems to source from the ascending colon.