My dad took
Flomax, and definitely had the dizziness issue, which is a result of
blood pressure changes. He was 30+ years older than you, and had prostate cancer, so your experience may be very different.
I don't know if you have prostatitis or BPH, or both - https://www.healthline.com/health/enlarged-prostate/prostatitis-and-bph That's up to the doctors. Has anyone been able to examine you or do any blood work or anything?