It's quite likely it's some sort of infection. You need to see a gp or gyn to get checked out and discover the exact cause.
Have you been checked for a bladder infections/UTI's? To have it going on for a year doesnt sound like a good thing. Your best bet is to get checked out by a doctor, make sure it isnt an infection left untreated as it can effect your kidneys etc.
UTI maybe but since it is very common for you I would get checked out
UTI normally gives you a burning sensation while urinating, infection in the bladder hurts when you squeeze. You should definately get it checked out. Good luck.