Pain in penis

I have had a condition for some time now. It's a long story and yes I have gone to many doctors, I believe I can be helped but I need to go in the right direction.
Starting in '99 and lasting to about '02 I had constant pain in my penis, ranging from an URGENT feeling of needing to urinate, to a sharp burning feeling to both. I remember that it started to hurt in earnest after masturbation. I was treated for UTI, prostatitis, took anitbacterial drugs,
had an MRI, Cat scans, and nothing was found.
Before this started and lasting through most of the period I continually battled with constipation.
I turned to laxatives to relieve my continual constipation, (yes it was stupid)
I also found that there was an unexpected side effect to not straining to have a bowel movement, my pain was relieved. For the next few years, up until last month, I took laxatives every few days. Occasionally, my pain would return for a brief period and disappear. Now that I have stopped taking laxatives, it has returned, and I am convinced there is a connection.
Masturbation definitely affects my pain, it can be at a very low level, but after ejaculation, (in which I feel a burn during ejaculation) my pain will intensify for short periods that are becoming longer and longer. After ejaculating yesterday evening I am still in pretty intense pain.
This is not in my head. I am certain that it is a referred pain, but from where?
Please help I know I cannot be the only person that has experienced this.
Thank you