Have an iud for a month. last couple of weeks i've been getting very sore after sex. i also have been itchy. already been tested for stds-clear

Yeast infection?: These symptoms suggest a vaginal yeast infection, which doesn't show up on routine STD testing. It's not an STD. Try an over-the-counter yeast treatment -- look for a product ending in "azole" (miconazole, clotrimazole, etc). You can use the cheapeast; they all work equally well. See your doctor promptly, preferably whoever put in your IUD, if the symptoms don't clear up within a week.