Passed a kidney stone about a month ago, still some throbbing pain in the left lower back area. is this normal?

Likely yes,,: You've just passed a kidney stone, which caused trauma to the inside of the ureter, the tube that urine goes from the kidney to the bladder in. This results in pain that may continue for a while before it subsides. If it doesn't go away and/or if it doesn't get better soon with simple pain meds like Tylenol, (acetaminophen) go see your doctor for an exam and possible treatment. Good luck.

Residual pain: Kidney stones may be solitary or multiple. Kidney stones may fragment. As a stone passes, it often scrapes the ureter and causes bleeding. These rough irritations can cause ongoing pain, but ongoing pain is unusual. Ongoing pain suggests a second stone or a fragment of a stone. A urine analysis and culture and ultrasound are next steps. Forcing fluids up to 3-4 liters per day is essential.