Is it a UTI?

Erin • NH/ live free or die
How can you tell if you have a UTI? Please be spacific! I've never had one before and I don't know if I should go to the doctors. I'm in some pain but it's not that bad. Just some sharp pains every now and then. I also have to pee all the time but barely anything comes out. Also the pain is only on my left side.