I had sex last night and then today i am having a light pinkish bleeding why is this?

Bleeding: After intercourse is usually due to mild trauma within the vagina or impending menses. In rare cases it can be a sign of cervical abnormalities, this is usually when bleeding occurs persistently, meaning every time sex occurs. Bleeding can also occur due to hymnal trauma. So, nothing to worry about now unless this happens all the time after sex then get checked. Get routine Pap smears.

I do not know: Maybe your cervix or internal vaginal area was inflamed by the act of sexual penetration of the mans penis, and the mild pinkish bleeding is caused by that. If it persists, see the GYN for an internal exam. Good luck.