Lump in my testicle tubes leading from the testicle to the ureatha

hi i am a 13 year old teen who is experiencing a problem in my sac whitch is a lump in my testicle tubes leading from the testicle to the ureatha this lump is only on the left tube but it will change in sizes weather or weather not i touch it and it can be squeezed to a hard limit before it hurts along with the fact that it will change shapes and it worries me to and extinct point please any help commits questions or answers will truly be appreciated please can sombody help me b/c it worries and scares me