What Causes Swelling And Burning Sensation In The Labia Post Child Birth?

I had a baby 4 months ago and decided around 6 weeks to have sex with my husband. Everything went fine but almost immediately after I started having discharge. It stated out clear and watery and now nearly 3 months later the discharge is yellow with some blood. My labia are now swollen and red and they burn very badly especially when I go to the bath room. I had a pap and culture both came back normal. I was just diagnosed with thyroiditis and started on meds about a week ago. Are these problems connected some how?