ESWL has a few side effects, which may include the following:

The most common side effect is pain caused by passing of fragments through the urinary tract.

Sometimes if stone is not fragmented using correct parameters of shockwave pressure etc. Large fragments can be formed and block the urinary tract. Thereafter blocking the urine flow. Such blocked fragments need to be removed with a ureteroscope.

Infection in the Urinary tract.

Bleeding around the outside of the kidney.