What Causes Stomach Pain After Intercourse, Bloating And Pain Around Anus?

Hello, I am a healthy 22-year old woman with two children. Recently, I have been having pains in my stomach after sexual intercourse. My stomach bloats up and I feel a little bit of pain when I stand or sit down. I see that a lot of women have pain in the anal area when they sit, but mine is more if I sit directly over my vaginal area. I feel as if I m swollen because I can feel my vagina kind of move as if it were swollen when I sit, but I don t necessarily have rough sex. I have had direct swelling from sex before where my vagina swelled outwards like you could see the swelling if you were to look at that area, but this isn t like then. I don t have any STD s, I had problem-free births, and in general have never had anything serious be wrong with me. Any suggestions? Thank you!