I was prescribed Sulfamethoxazole on Mon. evening for a kidney in...

I was prescribed Sulfamethoxazole on Mon. evening for a kidney infection. After taking it for 4 days, I developed a bad pain on the left side of my neck. Later on that day had a bad muscle cramp right below the inside of my groin. About 15 min. later had another one on the back side of my left thigh. Had me crying and couldn't straighten my leg. Figure it is the medication and stopped taking it. The next day, today, my leg muscles are sore and I feel like crap.I also developed a headache on the 3rd day.