What Causes Aching Pain In Right Testicle?

Hello Doctor, My name is Kevin and I m almost 20 years old. I m 5.9 and weight 159 pounds. Now on to the problem; for two weeks now I ve been having some aching pain in my right testicle. The first time I felt pain was during sex and I think it might be because of the pressure being put on my testicles. Now two weeks after I even feel pain masturbating. Even when I cross my legs, it results in some discomforting pain in my right testicle. It also feels rather painful when I touch to the right of the testicle area on the crotch. It might be me being paranoid but when I touch it it at least seems like to me that it s also shrunken in size. Does this sound like something you ve heard about and if yes is it something I should worry about?