What Causes Pimple On End Of Urethra?

Hi. I m a 24 yeah old male and have been experiencing a rather weird symptom recently. I had this really uncomfortable feeling on the shaft of my genital one day, but thought I could might be a rash from wearing a new pair of jeans I bought on the same day. But the next morning I noticed a small pimple right at the out end of urethra. I didn t know what to do, as something like this had never happened to me before. I popped it open and this white liquid came out as one would normally see from popping a pimple. Then I got this sort of bloody mark on the spot I just had squeezed the pimple out, which I still have after 3-4 days. The bloody mark though left a scab which had covered the area I had pimple, then now it s half gone. The problem I m concerned is that the whole area still hurts when I touch, as if it s inflamed, although it doesn t hurt when I urinate. The area I have this scab is now a little drier than other area and . I ve only had sex with my current partner for years and cannot recall any memory that would suggest I might have an STD. Should I be worried in this case? I just wanted to check...