Thank you for your query on Healthcare Magic.
Crying and paining while passing urine is due to passing concentrated urine, or any redness
in local area, or due to urinary infection.
Look and examine in genital area for any redness or inflammation suggestive of local infections like fungal.
Give plenty of oral fluids to increase her urine output.
Presence of pus cells of 4 - 6/HPF is suggestive of probable urine infection, but urine culture to be done to see the presence of infection.
Therefore consult the Pediatrician
for the examination and for investigations.
Hope I have answered your query.