Bladder squamous metaplasia found what is this and is it causing the kidney and bladder pain?

Change in the lining. Bladder squamous metaplasia means there are changes in the cells of the lining in the bladder, in a non-cancerous way, presumed due to frequent or ongoing irritation of the lining. The irritation is thought to be from chemicals like nitrosamines, cancer-causing toxins from smoking, bladder infections, bladder catheters, etc... Metaplasia itself should not be painful, so a urologist should examine.