There's a mild swelling in my left testicle since morning today; the right side is absolutely normal. It's not too painful, though there is a little discomfort when I walk (but not to an extent that I can't walk at all). There is no pain or blood discharge while urinating. However, there seems to be a slightly sticky, clear but painless discharge from the urinal opening. I'm not sexually active at the moment. I have always had protected sex and I last had it over a year ago. I have not had any injury, recent or otherwise, in the groin. I have been gymming (including lifting moderate weights) since the last 4 weeks.