Brief Answer:
Seems like muscle pull, since how long do you have this problem?

Detailed Answer:
Hi,

Welcome to Ask A Doctor service.

Could you please tell me since how long you have had this problem?

And does it happen every time you run?

Or did this happen only once?

A sudden onset pain immediately after running indicates musculoskeletal origin and can be easily confirmed on a proper physical examination.

Apply ice to the painful area 3 to 4 times a day and see if the pain subsides.

If you do not see any improvement, then you must consult your local doctor and get yourself examined to rule out any intra-abdominal pathology.

Drink plenty of water.

Take adequate rest.

Do not run too fast too abruptly.

Start jogging slowly, then increase the speed gradually.

For the time being, do not go for runs till you are completely free from pain.

You can take an over the counter pain killer like advil 400 mg once.

I hope this information will be help.

Wishing you speedy recovery.

Best regards

---