It burns after i urinate and some discharge in my underwear what medicine can get at the pharmacy?

Diagnosis needed: An accurate diagnosis is needed. Is there a vaginal infection or urinary tract infection as the primary problem? You should have a clean catch urine culture and colony count to check for a UTI. If positive, antibiotic would be needed. If negative, a vaginal infection is likely and treatment depends upon the type. You should consult a physician or gynecologist for diagnosis and treatment.