I was recently put on nitrofurantoin mono for a uti and have been taking it for 2 days now. before i started medicine, my upper back started hurting and now it's gotten worse and moved to my chest. what is going on? i'm scared?

You should not feeling pain in your chest with a simple urinary tract infection or even kidney infection (pyelonephritis). Nitrofurantoin rarely can cause pulmonary symptoms and chest pain is one of them. Just stop nitrofurantoin and call your doctor for a replacement, drink more fluid in the mean time. Sometimes, a simple cystitis can be cured with 2 days of nitrofurantoin along with high fluid.