Concern

hi, i have not been tot he doctors as of yet but when i was younger i got mumps, a symtom of mumpy is swollen testicles, well that happened to me, i had to take pills in order for the swelling to go down but a risk of it was infertility, now that i am 19 years old i am a little bit concerned because my testicle has reduced in size by quite alot, i was wondering if that would be a cause for concern and if it could relate to testicular cancer? please contact me asap as my testicle has been reduced in size since i took these pill, i was 15 when i got mumps and now im a little bit worried, and i am starting to feel a little bit of pain from it than normal and it is alot more sensitive than the other testicle, it hurst it i even touch it a little bit to rough