I honestly hope he is..or in the ER at least..trying to picture doing a kidney ultrasound on oneself would be interesting to say the least.
as an RN and one who's had a major kidney infection two years ago that damn near killed me because "oh I can self treat this" trust me...get to a hospital/doctor's office and INSIST we investigate the source of this pain (lower back right and left of the spine that might radiate medially if it's stones) but some stones are very minute but still will hurt like the devil to pass. Or infection, I've never had a bladder infection so after visiting my physician we were on a wait and see a dip stick reveled no abnormalities. I'm assuming you did a dip stick OP?? But it just bypassed that and until it was very bad no bacterial was detected in the urine, once it looked like coffee though yeah then I was believed I had a kidney infection at the ER at 2am.
because I know this pain is my body's way of saying "hey something is wrong".
maybe you lifted the ultra sound and hurt your back? *lol* that can happen as as you know because most medical appliance sales folks think they have a medical degree too *rolly eyes* that it can be referred pain.
either way GO to physician or ER and assert yourself as well as you have here in the forums OP.
best of luck!! and happy New Year