Frequent urination, urinary retention

[efival2704@gmail.com]

Hello. I'm a guy from Russia, 21 years old. 4 years ago I started masturbating with “sperm retention” (I was getting an orgasm, but I was holding back the release of sperm so that I didn’t have to wipe it off later). After some time, I began to go to the toilet frequently, and urinary retention developed (I wanted to urinate, but I couldn't, and I had to sit on the toilet to pee. Now I mostly urinate while sitting, but outside I can do it while standing).
This winter, I had a "comprehensive urodynamic study" (CUDI) and was diagnosed with a hypersensory bladder, a hypocontractile bladder with a small cystometric capacity, and signs of detrusus-sphincteric dyssynergia. Also, ultrasound of the prostate gland showed echogenic signs of diffuse changes in the prostate gland (prostate size - 13 cm^3). I was sent to a contrast ascending urethrography because I could not endure the filling of the bladder at CUDI, and I'm afraid to do the urethrography because CUDI was painful. Should I do an MRI of the bladder and prostate instead of a urethrography?
I've tried not to masturbate for three weeks in winter (before the CUDI), and noticed a slight improvement in my condition (the stream of urine increased, but I don’t remember the frequency of urination, it seems that I also began to want to urinate less often). But then I continued masturbating and my situation began getting worse again, eventhough I stopped holding my sperm 4 years ago when the symptoms started.
How to recover? I plan to not masturbate again for a while, maybe 2-3 months, and see what happens. I believe that the body has developed a habit of straining during urination due to my sperm retention, and now my body needs to be given time for everything to return to its normal state.