As Gilly mentioned, this may be hormonal and associated with elevated conversion of testosterone into estradiol (E2). A complete hormone panel can be run and include the sensitive assay for E2 (as opposed to the broader assay used for women). Elevated E2 levels, if they are indeed the culprit here, would also result in difficult achieving or maintaining an erection as well as changes in libido.
TC1: 1996, right orchiectomy, seminoma stage I 3.5 cm mass, radiation therapy (peri-aortic & pelvic 27.3 Gy)
TC2: 2008, left orchiectomy, seminoma stage IA 5 cm mass, left & right prostheses, AndroGel TRT, surveillance at MSKCC