It could easily be a small kidney stone that caused irritation. That would certainly explain pink fluid and pain. I have had this experience. I had several before it was bad enough for me to have checked out.
I had a similar ongoing situation years ago with pink fluid, no pain though. After a good year of tests, scans, etc. I had a prostate biopsy and cancer was found. I elected for removal and the issue when away. At first my urologist insisted it couldn't be prostate but I persisted as it was taking an emotional toll on me. Best of luck.
Judi