Hello. Thank you for writing to us Unprotected sex is a risk factor for all STD s and therefore I suggest you to get screened for all STD s. Knee pain seems to be non-specific and unrelated. Tingling sensation at the tip of urethra without any urethral discharge could be either non-specific urethritis like irritation due soaps etc for cleansing this area Or it could be non-gonococcal urethritis/ NGU that may have got it from unprotected sexual encounter. I suggest a swab test for urethritis at 2 weeks for possible microbial cause of urethritis (swab test detects the DNA of microbes like gonorrhea and chlamydia). Swab test is sensitive and specific and should be performed at 2 weeks or later for it to be authentic. I also suggest screening for HIV and Syphilis at 1 month and this has to be repeated at 3 months for a conclusive test result. Testing for Genital herpes is earliest at 2 weeks and would detect circulating antibodies against virus in case you were infected. Besides testing, if you develop symptoms like urethral discharge, genital ulcers/ erosions, warts or growths in the genital region you must get yourself examined by a venereologist. Regards Always practice safe sex with a condom!!