The lab tests for gonorrhea and chlamydia are reliable evidence you didn't have eitehr of those infections. But if you had had chlamydia or gonorrhea, the doxycycline would have cleared them up (almost 100% reliably against chlamydia, 90% effective against gonorrhea). In any case, your symptoms don't really suggest any STD, especially the variable ease of urination with or without drinking fluids. And of course no STD can affect bowel movements in the way you describe.
As I have pointed out before, when a person suspects his or her own symtoms might be due anxiety or other emotional issues, they probably are almost always right. In any case, your symptoms do not sound serious and you definitely can relax about STD as a cause. Follow up with your health care provider if they persist.
Good luck--- HHH, MD
But whatever you had then could indeed be causing pain now, without necessarily meaning a new infection. People with previous ankle sprains often get recurrent pain in the ankle from time to time; and women with past PID (fallopian tube infection) often get recurrent pain without new infection; etc. The same can happen in any injured body part, without meaning new disease or injury.
If your pain persists, you should have it examined (and right away if you develop fever or testicular pain or swelling). But no STD causes the kind of pain you describe, or in the locations you mention.
HHH, MD