Hi,
I noticed this tiny pimple on my scrotum this morning after shower, it is small enough that I cannot see it without looking (I actually went looking when I found it to be fair).
Right now it is the only one and there are no noticeable blisters or anything. I have recently done a urine test for Chlamydia and Gonorrhea which came back in negative for both.
I've also worn a tight briefs and shaved recently.
Most likely this is related to you having shaved - you may have caught a hair follicle and the tight briefs may have caused further irritation. I would try a little liquid antiseptic on it such as TCP - dab on 2 or 3 times a day and see how it reacts. If it hangs about, wear some slightly looser briefs for a few days - skin imperfections like this can simply remain - if you think this may be sexually related, obviously, keep a close eye out for anything else developing …