Pure lemon juice.
No sweetener. Not from concentrate.
This has been used for years and often reduced the stone and the pain.
Otherwise - sometimes real pain medication is needed. Out-patients might be necessary to get a prescription so you can have relief until it/they pass.
My husband has kidney stones. He is not supposed to eat lots of peanut butter or peanuts or kidney beans, etc. Drink lots of water everyday - stone or not.
Let me know how you do.
To help dissolve the kidney stone, do this pranayam twice a day.Allow 3 months to notice the benefit.
Build up your timing gradually.If you feel tired or dizzy, stop and resume after one minute.
Kapalbhati pranayam -(Do it before eating) Push air forcefully out through the nose about once per second. Stomach will itself go in(contract in). The breathing in(through the nose) will happen automatically. Establish a rhythm and do for 20 to 30 minutes twice a day. Children under 15 years – do 5 to 10 minutes twice a day.
Not for pregnant women. Seriously ill people do it gently.
If you can get patharchata leaves, then eat two leaves a day.
There are remedies for kidney stones, but if it's no longer in the the kidney in don't know. the main herb is called gravel root, which is pretty self-explanatory. One formula is Stone Free by Planetary Herbals.
Goldenrod extract might help, too.