Firstly, what were you tested for and what did the doctor treat you for? Some STD's have become extremely resistant to antibiotics. So it depends on which one you had or may have had. For example gonorrhea is treated with a shot of Azithromycin and Ceftriaxone. Unless you are allergic then they do other dual antibiotics. So did anything come up positive or is the doctor treating just in case (empirically). You should also get tested for Ureaplasma urealyticum as that can give you those symptoms. Also, a regular urine culture to make sure you don't have a urinary tract infection. Some bacteria would be resistant or not treatable with those antibiotics. If these all come up negative I would see the urologist. Sometimes you can just have prostatitis or something not related to the sex.
Thank you for your time and knowledge. Anything definitive happens I'll be in touch.