Full bladder feeling consistently with cramping on left side? I had emergency gall bladder surgery about 2 years ago? Sour stomach

Possible retention . In a male over age 55-60, post-operative urinary retention is quite common because of the effects of surgery, anesthesia, and medications causing swelling/tightness of the prostate and retention of urine. A UTI would be another possibility. Avoiding constipation, warm tub baths, limiting use of pain meds may be helpful things you can do. Otherwise, recommend call your md and/or surgeon for advice.