Hi I Am 18 Years Old, I Have Had Pain

Hi I am 18 years old, I have had pain in my middle back and pain in my left side also experiencing flutterings in my left side, I have had a renogram recently and found no problems with my kidneys, I do take antibiotics every night to prevent infections but I can't tell if it's my kidneys hurting or in injured my back? Hope someone can help, thanks in advance