Don't get meds before getting tested. If you get the wrong meds, you could screw up your testing for weeks.
I agree with geno that you need to test, though. I know it's crazy in a lot of places, but if you can get to your doctor, an STD clinic or even an urgent care, at least test for gonorrhea, chlamydia and NGU.
If you've had unprotected sex and are experiencing burning in your penis then you should be tested. Do you have STI clinics where you are from?