4mm kidney stone

saturday around 3am my back started to hurt constantly and felt like it was radiating throughout my whole lower back. I ended up going to the hospital and i am in so much pain and im switching between being hot and cold but i was sweating perfousely. I also couldn’t keep any water down i was throwing up every single sip. eventually they gave me a shot of toradol and i did a CT scan and i have a 4mm stone in my distal left ureter and another 2-3cm in the lower left pole. They gave me so Flomax and prescribed some toradol pills and said i would most likely pee it out. I check my “My chart” and it said i have mild hydronephrosis which worries me. after the hospital i felt great all day no back pain and no trouble peeing either. today around 1:30 my back pain starting again so i took a toradol and it went away for a little while but now the pain is back mildly and it’s only been 2 hours since i took it. I’m genuinely worried about this kidney stone even though ive read 4mm is small enough to pass naturally my mother in law who used to be a nurse keeps telling me if it doesn’t come out tonight i need to go back to the hospital and get them to break it up because my symptoms are bad. Can anyone tell me what the back pain comes from? does it mean the stone is sliding down my ureter? and will the back pain continue until i piss the stone out? my back hurts so bad and the only pain meds they gave me was toradol and i can only take that for 5 days. google says seek medical attention if you have these certain symptoms and i legit had every single one the other night and they made it seem like this is nothing major and itll pass. should i continue to be concerned or should i fully trust the dr word?