Kidney related issue. Should i do now?

Hello Doctor, For more than 1 year, I have had right-sided pain/heaviness between the ribs and abdomen, sometimes felt toward the back or lower right abdomen. It usually starts when I hold urine, even for a few minutes after drinking water. Since yesterday, it has become continuous. I also have a weak/low-pressure urine stream and sometimes feel incomplete bladder emptying. After drinking only ~200 mL water, I may get an urge within 15 minutes and urinate 2–3 times within a short period. Previous ultrasound showed no kidney stone or hydronephrosis, but around 273 mL urine remained in my bladder after urination. Previous KFT was normal. Could this be urinary retention/incomplete bladder emptying, and could it be affecting my kidney? What tests should I do now? Thank you.