Pain above testicles

A few weeks ago I was sitting at home and my left testicle started to ache, I've had this feeling before when I was little so I thought nothing of it, but it lasted much much longer and was more intense. The next day the pain hadn't gone away I felt around in my scrotum and found out that the pain was actually in what I think is my vas deferens so I booked an appointment and went to see the doctor. She asked for a urine sample and poked my balls a little. Then she sent me to get an ultrasound, but it didn't reveal anything other than that I have a bit of calcification and the urine came back clean too. The pain went away but now its come back and its starting not only to hurt in the scrotum, but also is shooting up into my body. I'm not sure where it's going it stops at about the height of my bladder which lead me to think that it was a vas deferens infection, but it doesn't hurt when I ejaculate. I have had a feeling like I was getting a cramp for a little while, but that feeling went away. Occasionally if I sit in a position where my belt pushes down on my abdomen it goes numb or something like that for a bit. Has anyone ever heard of something like this, I have considered prostatitis or kidney stones, but considering I'm only 19 this doesn't seen too likely. My doctor said another thing might be happening and it's that urine is getting into the vas deferens and causing a sterile reaction.