Urinary retention caused by finasteride?

Hi all, I hope you're well.

In February, I (21M, 170cm/5'7, 43kg/95lbs, Asian) started taking 1mg oral finasteride daily for hair loss. Two to three weeks into treatment, I started experiencing urinary retention issues and pretty severe genital discomfort, along with some penile shrinkage. I stopped the medication and all of the side effects ceased within a few days.

About a month later, I decided to try taking 1mg oral finasteride again but every alternate day instead. After just two doses of the medication, I began experiencing the urinary retention issues again. It was milder this time but three months later, the retention has yet to fully subside. It fluctuates in terms of severity; during my worst bouts, I have to visit the toilet 4-5 times within a 20-minute window before I feel like my bladder has been fully voided.

Over the last few months, I've done two urine tests and one renal panel and the results for all three investigations came out normal. I don't have any underlying medical conditions, although I am recovering from a spontaneous pneumothorax that I sustained in January, which resulted in me having to get a chest tube insertion and VATS. I had some issues with urinary retention and constipation while I was hospitalised but it cleared up well before I started my first round of finasteride so I'm assuming it was just caused by shy bladder/bowel issues.

I'm pretty baffled because I have never encountered any other incidences of finasteride causing urinary retention in patients. I'm assuming it's having some weird effect on my pelvic floor because diaphragmatic breathing exercises and Reverse Kegels tend to provide me some relief from my symptoms. It's also worth mentioning that I've had pretty bad urinary habits for most of my life (I would often hold my pee for hours until I got home from work/school because the public restrooms were filthy) and I have a tendency to clench my pelvic muscles during masturbation, which at a point in time I was doing quite regularly (like 1-3 times a day).

Have any of yall encountered similar issues on finasteride? Could it be because of increased testosterone levels (caused by the lowered rates of conversion to DHT) resulting in pelvic floor tightness?

Additionally, I've been diagnosed with gender dysphoria and intend to medically transition once I've leave home in the next few months. Am I likely to experience similar side effects on estrogen and other anti-androgens?

Thank you for reading and any insight would be greatly appreciated. Also I really apologise if this is the wrong forum to post this in 😭