Suasdaguna
Hard liviing isnt the cause, its more biochemical and the shape of the kidney thats to blame. Becoming dehydrated is a cause though, so fluid intake is critical. Proprietary isotonic drinks are very good. If you have access to an occupational health physician they will be able to advise you on the causes as the blood tests reveal much, and give advice as to diet and most of all, fluid intake. Food and drink high in calcium are best limited, so reduce the cheese and milk.
The pain, as I'm sure you know, is when the stone moves from the kidney into the tube connecting the kidney to the bladder. If the stone is passed through the bladder you wont need any intervention.
In a way you are lucky. 5mm is about the right size of stone to be obliterated by lithotripsy, which is sound waves used to shock the stone into fragments which will pass through the urinary tract. If there are stones which stay in the kidney or ureter then lithotripsy is the best choice. It doesnt hurt, isnt even uncomfortable during the process, needs no anaesthetic and is completed in about an hour.
Surgery if needed, also isnt horrendous as most stones can be taken out with a camera technique which a small camera, very similar to that which engineers look inside engines, is used to take stones out of the urinary tract. Its known as dormia basket extraction, or endoscopic renal surgery. No incisions are necessary although it usually means a general anaesthetic.
Surgery usually is undertaken if the stones are large (Ive seen 30mm stones) or a shape that gets stuck in the kidney (staghorn calculi) or there are an awful lot of them. This is pretty much at the far end of the scale of treatment. Its hard to tell at the end of a computer but I guess that this wont be necessary as about 80% of kidney stones are dealt with by lithiotripsy or endoscopic dormia basket extraction. Hopefully the stone will pass normally.
You have my best wishes and I hope this has helped.