Misscroft,
sorry you find yourself here. I'm guessing the level 4 is the PIRADS or Likert score from the MRI, which means there's something that needs checking out, but an MRI can't generally diagnose cancer. This is the purpose of the biopsy. But the level 4 might refer to something else - difficult to tell when it's been passed through several people verbally.
I think most people in your dad's position would have back pain, regardless if they had cancer or not.
You really just have to wait for the biopsy results, which will be an anxious 3 weeks or so.