One consideration would be Peyronie's disease. This is a disease characterized by a plaque, or hard lump, that forms on the penis. The plaque develops on the upper or lower side of the penis in layers containing erectile tissue. It begins as a localized inflammation and can develop into a hardened scar.
The hardened plaque can reduce flexibility, causing pain and at times forcing the penis to bend or arc during erection.
You may want a referral to a urologist to see if this is the case. Treatment for this includes injected chemical agents such as collagenase, steroids, and calcium channel blockers directly into the plaques. There are no consensus statements demonstrating clear efficacy.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Thanks,
Kevin, M.D.
I had a problem that sounds similar to yours. Pain with erections, mostly on one side of the penis and at the base, and the vein on that side was more prominent/swollen. It got to the point where the slightest arousal caused pain.
I went to my doctor, initial diagnosis was thrombophlebitis of the penis (mondor's disease). Got a referral to a urologist. I started taking bromelain, a pineapple stem extract that helps (among other things) with thrombophlebitis. Within a day, the pain improved somewhat.
Went to the urologist, who said that it couldn't be thrombophlebitis, as it would have to be painful all the time, not just on arousal. He did diagnose a pulled muscle or muscles, and thought the bromelain might also be somewhat helpful for that (anti-inflammatory). Takes time to heal, warm soaks might help somewhat, he said.
I am looking into myofascial therapy, as this has helped me with other conditions and is usually something I can do myself once I figure out where the muscle to target is. Myofascial problems occur when a muscle is over-taxed. The muscle then knots up, doesn't work properly, and can refer pain locally, sometimes far away.
Here is another page that discusses the research on that type of pelvis pain:
http://aphrodisiology.com/pelvis-pain-sexual-dysfunction