I am having testicular pain. Is there any significant danger, and what should I do about it?

I am a 16 year old male, and I am having pain localized to the bottom of my left testicle. For a few months about a year and a half ago, I was having similar pain. While it was less severe, it was more frequent. After a while, it simply went away and i thought it was gone until about a week ago when the pain returned stronger than ever. Every other day or so, for the last week, i have had episodes of testicular pain (about a 6 on a scale of 1-10) that last about a minute, then go away. If i touch the bottom of my left testicle during an episode, the pain is significantly increased, but it does not hurt to the touch at any other time. I'm not sure if this is relevant or if this happens to everyone, but my testicles sometimes feel very sore after masturbating. I have done a bit of research, but nothing seems to quite fit my symptoms. I did see one website in which it was suggested that excessive masturbation could be the cause, but I masturbate once a day with rare exception, which would not be considered "excessive." Another website suggested a bacterial infection, but I have been on antibiotics multiple times over the last year for sinus infections, and I do not have a Fever or any other symptoms of infection, so that is pretty much ruled out. Some websites suggested that it may be an STD, but I am a virgin which rules that out. Another has been testicular torsion, which, as this has been inconsistent pain for more than a year, it seems unlikely. I have also come across testicular cancer as a possibility, but i checked and did not notice any abnormalities or differences between my two testicles. Additionally, there is absolutely no history of cancer in my family except for my grandmother who has lymphoma so mild that nothing needed to be done about it. Finally, there has been no potential injury to my testicles. Do you have any other ideas of what it could be? Do you think there is any significant immediate danger? Thank you so much.