Is this sensation painful?
Anything make it better/worse?
Any other medical history?
Any problem with getting/sustaining erections?
Any discharge from the penis?
Any testicular pain/swelling?
It would be very helpful if you could answer the questions above first.
Ok, all good answers. Now you said, this happens everyfew minutes? How long have you been experiencing this? Can you describe it any other way? Is it a shooting sensation / electrical / pins & needles etc?
Well, all I can offer you now is reassurance that this is most likely very benign. I'll do some research and get back to you tomorrow if that is ok. The link below lists several of the most common causes of penile pain, none of which I feel apply to you.
Thank you for your patience.