I Have A Swollen Testicle With Pain Some Burning Sensation

I have a swollen testicle with pain some burning sensation penile leakage and i have only slept with my girl .She's in the medical field i have question she said that there is no concern she haven't been out the relationship. Now my question for you is what can cause this , to add a lil more information i usually put the powder deodorant down there for sweating.