I experienced something similar a few years back. It did feel like a lump or prolapse of some kind, just behind the pubic bone. I had had similar symptoms, as though there was a misplaced tampon, but it was only when I summoned up the courage to do a self-exam that I felt a lump/prolapse. I completely freaked out and phoned the GP practice in a panic.
Neither the practice nurse nor the GP could find a prolapse – though I did wonder whether that was just because I was lying on my back during the examinations, so gravity wasn’t pulling it vertically downwards. My GP did a speculum exam and saw a “dangly thing” that had probably grown off my cervix. He said it was completely benign and not that unusual, but he wouldn’t try to remove it as they sometimes bled quite a bit. So I was referred to a gynae, who confirmed from visual inspection that it was indeed a benign “dangly thing” and quite common. She removed it; and I asked to see it. It was the thinnest “dangly thing” imaginable; but she explained that the vagina isn’t just a muscle that expands for the purposes of intercourse/childbirth, but has a lot of nerve endings and is very sensitive.
I’m now some 15 years post-menopause, when things generally go a bit south anyway, but I’ve had no symptoms since. Whatever I felt when I did that self-exam all those years ago could well still be there but, if it is, it isn’t obvious at all.
I would suggest seeing your GP and asking for a gynae referral. I still remember how miserable it was to feel something wasn’t right every time I stood up or walked about.
(If anyone could supply the medical term of the “dangly thing”, I’d be grateful. And would add to the knowledge every woman should have of what various things can happen to our various bits and pieces.)