I just finished peeing and I have to pee again. What's wrong?

Urinary tract infection can cause frequent urination, urgency, and pain in urination. This is because bacteria or pathogens infect the urinary system. It stimulates the mucous membranes of the urinary system to dilate, congest, and exude inflammatory substances in the blood vessels, thus causing the above symptoms. When older men suffer from BPH, the enlarged prostate tissue compresses the posterior urethra, thus narrowing and narrowing the lumen of the posterior urethra. Hyperplastic prostate tissue often has congestion, which affects the mucosa of the bladder at the same time, thus causing the situation of wanting to urinate just after urinating. Lower ureteral stones also show the situation of wanting to urinate just after urinating, which is because the stones move in the ureter and it stimulates the muscles of the ureter. At the same time, it will also affect the muscles of the bladder wall, causing bladder wall muscle dysfunction, so it shows frequent urination and urgency.