Kidney stones are hard deposits of minerals and salts in the kidneys. They can actually deposit in any part of the urinary tract and can be a cause of urinary retention. Bacteria can also begin to grow around the areas of deposit leading to urinary tract infections. 
They are formed when the urine becomes concentrated with crystal-forming substances like calcium, oxalate, or uric acid.
Kidney stones may not cause any issues until they attempt to move from the area where they were formed resulting in a block of urine flow through the ureter, causing spasm and severe pain. 
Kidney stones can cause the following symptoms;
- Sharp, severe pain in the side, the back, and below the ribs.
- Pain while urinating.
- Burning sensation while urinating.
- Pain radiating to the groin and lower abdomen.
- Cloudy or foul-smelling urine.
- A frequent urge to urinate that is more than the usual.
Pain is the most significant symptom experienced with kidney stones and it might shift to a different location or increase in intensity depending on the location and movement of the kidney stone.
There are about four major types of kidney stones; most times, the cause of a kidney stone can be determined once we know the type of kidney stone it is.
- Calcium Stones: They may occur in form of calcium oxalate or calcium phosphate.
- Struvite Stones: They are known to grow large quickly and usually form as a result of a urinary tract infection.
- Uric Acid Stones: These are usually seen in people with gout. It can also form in people who eat a high protein diet or people with some metabolic disorders.
- Cystine Stones: Cystine stones are rare. They are found in people who suffer from a hereditary disorder called Cystinuria.