Azithromycin 3 Day Dose Pack and bumpy rash

I was prescribed the tripack for bronchitis. Day 3, I experienced stomach pain, diarrhea which I know is not uncommon. On day 4, I started having some knee pain. A couple days after, I experienced stiffness and pains in my hands and ankles. & then the itching starting, mostly on my feet- top & bottom- I felt like I was going to jump out of my skin. I also had some itching on my legs with a raised bumpy rash. My hands & ankles are very swollen and it hurts to type this. My doctor said it has to be a severe side effect of the tripack. He has put me on Darvocet & Prednisone. I hope those work.