Brief Answer:
Sounds like a hernia.

Detailed Answer:
Hello Mr. XXXX,

Thanks for the question. I can understand your pain and concern.

From the description you have provided, I feel you might be suffering from a hernia in the inguinal region, or it could be a varicocele.

Both these conditions can at times give you pain due to the fact that some minor anatomical adjustments do occur while you get an erection.

Loosing erection may be because of the impingement of the blood vessels that supply the shaft of penis, the penis becomes erect and hard because of the venous occlusion and pooling of blood in the corpus cavernosum(Large sac like veins in the penile shaft), so if there is an abnormality in this, it will lead to loss of erection.

Loss of erection can also be due to the pain you experience, pain activates certain brain areas which can make you lose the erection.

This is the most I can tell you about your condition based on the limited information that is available to me, to accurately identify the issue I would suggest you get an Ultrasound scan of the abdomen and penile shaft and scrotum and I would strongly recommend paying a visit to your urologist at the earliest for a thorough clinical exam which will give an enormous amount of information regarding what is going on.

I hope I have answered your question adequately, please do not hesitate to write back to me if you need further clarifications or in case you have additional questions for me.

Wishing you speedy recovery.

Kind regards,

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