Back pain UTI

I went to urgent care for a UTI yesterday. I was given an antibiotic and a pain reliever. When I was there I didn’t have any abdominal or back pain, however when I got home it started hurting. I am taking both medications as prescribed.

I don’t have a fever, vomiting, chills, any of the symptoms of a kidney infection other than back pain. Do I need to go to the ER for this?