What could be the cause of both my sides hurting and lower back pain at the same time?

Let's see....how about anything? You will need to see a doctor as we can't diagnose you online.

The list long as to what could cause that. It ranges from muscle cramps, nerve issues, to organ issues. It is almost impossible to say online. This would be a really good time to go and get it checked out by a professional.

1) Kidney infection; or
2) Bladder infection; or
3) Pulled muscle; or...

You see, we don't know your medical history, we can't run the necessary tests to determine what is wrong with you. You will have to see your doctor.