I got treated for chlamydia on march 6 and had unprotected sex on march 16 and bled during n aftr with no pain no nothing is this normal?

Post-coital bleeding: Bleeding after sex (post-coital bleeding) is common. Bleeding may or may not be a sign of sexually transmitted infection which is often times silent. There is only one full proof way to avoid stds but it's not much fun: abstinence. You can minimize risk of std by using protection, eg condom. Unless you're in mutually monogamous relationship, there's no reason to avoid using condom + prevent prego.