Your urinary tract is the system that makes urine and carries it out of your body. It includes your bladder and kidneys and the tubes that connect them. When germs get into this system, they can cause an infection.
Common symptoms are painful urination, or the feeling that you need to go, but nothing comes out. Check out this article for more UTI symptoms.
Antibiotics prescribed by your doctor will usually cure a bladder infection. It may help to drink lots of water and other fluids and to urinate often, emptying your bladder each time.