What Causes Severe Pain During Sexual Intercourse?

I have a birth control implant in my arm that lasts three years. I last year had a tampon stuck inside of me creating constant vaginal bleeding for over a month, with a horrible stale blood smell. After I went to the hospital and had a lodged tampon removed I was fine. Now recently I started my period, it was normal, two days after it had stopped it started again. No concern because my irregularity is common with the birth control. I have not stopped bleeding for 3 weeks now. I don't think I have a tampon in there like before and deep sex really hurts. Do I maybe have another tampon inside, is it just the birth control?