D.W.
He should call his doctor and make an appointment soon.
I was 7 weeks postpartum when I found a small, pea-sized nodule on my collarbone. No one thought it was anything, but I was asked all the normal questions: are you nauseated? do you have night sweats? are you fatigued? are you losing weight?
I was 7 weeks postpartum! Everyone thought it was related to pregnancy hormones getting out of my system and having 2 kids under the age of 2. Then, 2 days before my 33rd birthday, I was diagnosed with cancer.
Testosterone is the main hormone related to male sexuality. There is a condition discussed on WebMD called "AndroPause" - here's a link for you to review:
http://www.mayoclinic.com/health/male-menopause/MC00058
And here's what MayoClinic.com says about "Man-o-Pause":
http://www.mayoclinic.com/health/male-menopause/MC00058
I hope it's nothing, but it's always better to be safe than sorry.