I have severe pain while/after urinating. this is after four days of nitrofurantion mono-mcr and pyridium (phenazopyridine). what now?

You need ..l: To get a urinanalysis and urine culture to see what is going on.

See your doctor: Nitrofurantoin is a good drug for empiric treatment of uti, but failure of treatment suggests something else going on (this could be a bacteria resistant to Nitrofurantoin (most likely) or a different diagnosis/complication). I would go see your doctor again for re-evaluation, including repeat ua and culture.