Semen colour changes and a bendy feel on testicle

Dear Ask The Doctor: Hi, im 16 and a virgin. A couple of weeks ago i i found that it was harder to 'keep' an erection and harder to get one. A couple of days later i found that it took longer for me to ejaculate, and when i did ejaculate there appeared to be less semen than normal. a couple of days later i felt a lot of pain in my right testicle, so bad that i could barely walk. after a sleep the pain had gone away i thought everything was back to normal, i found that i could 'keep' an erection and they were easier to keep, the time it took to ejaculate had also gone back to normal, but my semen looked a bit off colour. i had not masturbated for about 6 days and i heard that it is normal for semen to be slightly off colour after going for a small while without ejaculating, so i thought nothing of it. the next day my semen appeared to be back to the normal colour. i did however think (and i still do think) that my right testicle is a bit swollen, i dont know if it is actually swollen or if its just me worrying and jumping to conclusions. anyway yesterday i had not masturbated for 2 days but i got a really bad pain in i think both testicles this time, once again i slept it off and today they felt fine, so i masturbated and it all happened as normal, but my semen look a little bit off colour again and it might have been a bit thick, or maybe it was just me. Last of all im not sure but i think i might be able to feel something near one tip of my right testicle, it does not feel like a lump, and it is very small and kind of feels like a bendy line, i dont know if it is just me imagining i can feel it when it is really just nothing, like a normal vein in my scrotum but any how i wanted some advice, so any help you could give would be greatly appreciated, thanks

Dear Anonymous: Semen can normally be white, off white or milky white in colour. Pink or red colour of the semen indicates blood and should be concerning. Also yellow or green colour changes may be due to the presence of infection. The small bendy feel that you notice is a normal anatomical structure called the epididymis which is a narrow, tightly-coiled tube from one end of each testicle, connecting to the tube called the vas deferens. This is the transporting system for the sperms from its production site, the testes, to the storage site and ejaculation.