16 weeks and 2 days pregnant with pains

Yesterday at 9pm I went to the ER with period like cramping doctor checks me over makes me pee in a cup. He says he thinks I have kidney stones! But not sure because can’t really do anything to completely confirm it. Was discharged at 12am by the time I got home cramping was gone but my my left side of my back/side has a tight pain and has started to feel like burning feeling nauseous and super hot when that happens. Went back in at 7am looked at the baby everything looked good no bleeding heart beat was strong he said low risk of miscarriage and was told just take some Tylenol and was discarded at 9am but I’m just still having horrible pain and it helps if I lay in the bath but only for a hour or so. Just wondering if anyone has had this problem and it has been kidney stones or anything else?!