Sounds like a bladder infection. It's common in pregnancy. Drink cranberry juice and call your Dr. They may want to give you some antibiotics to clear it up.
I would ask a doc but sometimes baby pushes against bladder and then once your bladder is empty baby will shift to fill extra space that might be the cause of pain
Go to the doctor and have them take a look. Could be an infection and you want that cleared up as soon as possible.