Hi and thanks for the query, It might be very helpful if you get examined by a physician. association of this sensation to painful urination or fever might be useful especially in older men as this could indicate prostatitis. A clinical evaluation is compelling as the tenderness could also due to a local infectious or inflammatory process. Knowing exactly when this has been going on, the previous medications ever taken if any, and the response to the various medication could help orient the examining clinician. An allergy either to the type of pants you put on could not also be underestimated. I suggest you consult your primary care physician for a proper and complete clinical review. Best regards. Bain LE, MD.