Hello from JustAnswer.
If the pain and soreness is a continuing pain or soreness, that is not as worrisome. The duration of pain or oreness after a biopsy will vary, but can last up to a week or two. The concern would be if the pain or soreness is generally getting worse. There can be some variability in pain or soreness from one hour to the next, but if the overall pattern of pain or soreness is getting worse or if the pain or soreness today is worse than any pain or soreness that you had yesterday, that would be worrisome. In addition, if there are any associated symptoms, such as blood in the urine or pain with urination, that would be worrisome.
As for work, there are many doctors that would say to avoid heavy lifting for 2 weeks after a biopsy. But even those doctors that are willing to consider resuming activity sooner would usually want to continue to restrict activity if there is continuing pain or soreness. If you need a note for work, you will need to contact your doctor, but if you can simply make the decision yourself, it would be reasonable to avoid heavy lifting for another week.
It is also worth noting that it would also be wise to avoid activities that jostle the kidneys, such as jogging, aerobics, or any bouncing activities.
If I can provide any additional information, please let me know.