Pain in the right flank or lower back, could be due to muscle spasm/
kidney stones/hernia.
Please meet an abdominal surgeon, who can further evaluate and examine the area.
If it is associated with burning urination it is more likely to be a urinary stone/infection.
So please get an ultrasound scan of the abdomen and pelvis.
Next Steps
Please get a USG abdomen-pelvis scan done. With the report, meet an abdominal surgeon by physical consultation/atleast online consultation if possible.