After having unprotected sex and use morning after pill, I experience thick heavy yellowish discharge,but itz not smelling bad, and not ithiching! What will be the problem?

Yellow discharge indicates possible infection. We can't tell you what the infection is, if you have one. There's no way to diagnose online. You'll need to see your doctor for a diagnosis.

Good luck.

Agree, it is an infection ( most common cause), time for doctors visit.