The bladder is a hollow organ in your lower abdomen that stores urine. Many conditions can affect your bladder. Some common ones are

• Cystitis - inflammation of the bladder, often from an infection
• Urinary incontinence - loss of bladder control
• Overactive bladder - a condition in which the bladder squeezes urine out at the wrong time
• Interstitial cystitis - a chronic problem that causes bladder pain and frequent, urgent urination
• Bladder cancer

Doctors diagnose bladder diseases using different tests. These include urine tests, x-rays, and an examination of the bladder wall with a scope called a cystoscope. Treatment depends on the cause of the problem. It may include medicines and, in severe cases, surgery.

NIH: National Institute of Diabetes and Digestive and Kidney Diseases