I had my period on 28 may 2016 and had unprotected sex with no ejaculation on 6 june. after sex i'm having constant mild pain in the lower abdomen .

GYN exam: You must be seen and evaluated with a pelvic exam to rule out inflammation, infection or a vaginal tear.

See a gynecologist: While it's possible that unprotected sex without ejaculation can still lead to pregnancy, you may be at risk of other problems like infections for which you should be seen by a gynecologist for testing. If the pain is getting worse, this can be an emergency -- pelvic inflammatory disease.