What Causes Tenderness And Pain In Testicle?

I'm 23, been diagnosed with epipdiymus and have seen the urologist who gave me dyoxyciclyne ( I know I spelled it wrong). This has helped but the right testicle is still very tender/sore and some general unwell feeling still. I've been fighting this for a year or so and any help would be great. All cultures are negative as well..