Pain in Testicle

  I am 38 yrs old, and have been experiencing pain in left testicle area for @2+ weeks. Have self-examined-detected NO lump. Also seen family MD who examined and did not detect any lump/pathology. However after sex and while erect, I again examined my testicle and detected a small but distinct mass/lump on the lower side. Again, no sign of it when flacid. I originally suspected bruising from extended sessions on stationary cycle was causing pain (and pain/discomfort does pick up after cycling). Any insight or direction will be appreciated - including whether this might be a coincidental discovery rooted in the increased blood flow (e.g., circulatory)? Thanks in advance.
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Dear Nick,
Thanks for your question.
A persistent testicular pain, even in the absence of a mass that can be felt, is of concern. I would suggest that it be examined by a urologist. An ultrasound may be required as there are intratesticular tumors that cannot be felt.
Testes usually swing out of the way when one