It can be caused by multiple conditions, such as UTI( urinary tract infection) or kidney stones. It can be due to some medications, like blood thinners, or certain painkillers.
Whatever it is, you need to see your doctor. It is not something that will go away on its own, and it is better to treat it earlier than later. They will advise you to take a urine sample for analysis, and that way determine what the problem is.