What Causes Pain In Lower Abdomen After Ejaculation?

I am a 60 year old male, six feet tall and weigh about 250 pounds..Upon ejaculation, I get a sharp stabbing pain on the right side in my lower abdomen above the pelvis. It is extremely uncomfortable, interferes with the enjoyment of orgasm, and lasts for a long time. The spasm/pain usually takes at least 10-15 minutes to subside, and the area is often tender to touch for a good while after the sharp pain is gone. The muscle cramp/spasm is so severe that it is causing me to avoid sex. What's causing my problem? Is this an inguinal hernia? What can be done to correct this? Is there a way to address this medically or is surgery required? (I had a kidney stone pass about 15 years ago and an umbilical hernia that was surgically repaired about 10 years ago.)