What Causes Lump Inside The Vagina? Is It A Sign Of Pregnancy?

Hi, I m 21 years old I found out I was pregnant when I was about 7 weeks. I had a medical abortion exactly a month ago today. I had my follow up appointment a week after the abortion and the doc said everything was ok. My boyfriend and I had sex a week after the abortion and multiple times since then. (I have started birth control) I have not stopped bleeding since the abortion which I figure to be normal being that the doc said I could bleed up to 30 or 45 days. My problem is, is that my boyfriend keeps feeling like he is hitting something inside me while having sex. He describes it as a lumpy grape. I can feel it with certain positions but it doesnt hurt just feels weird. Now when I was pregnant and we would have sex, we both would feel this same feeling when we would have sex and I just figured it had something to do with the cervix and me being pregnant at the time. My question is, could I be pregnant again? (He has ejaculated inside me) I only ever felt this weird feeling when I was pregnant never before. I m a little concerned as to what this may be...any suggestions would be appreciated! Thanks