Causes can be divided according to the affected organ and they are Kidney
conditions (infection, pyelonephritis, kidney stones
, polycystic kidney disease), Bladder conditions (cystitis, bladder polyp, bladder tumor), Urethral conditions (Sexually transmitted diseases, urethral injury, vaginal inflammation), and certain bleeding disorders.
You should visit your urologist who needs to conduct a detailed examination.
I hope it helps. Take care and regards.