I'm 25 weeks pregnant and I get that same feeling sometimes, it's not an ask day thing but def moments where I stop and think what the eff was that? lol there are lot of things growing and stretching out can cause cramps and stinging sensations, ask your doc if it makes you feel more contoured but I wouldn't stress. As for the extra skin she is right, we tend to swell up down their because of the extra blood flow, I felt swollen down there and checked it out and was astonished by my double labia! No worries. Good luck!
I agree with Stacey. When I was pregnant, he would move and his head would press on my cervix and it felt like a bolt of lightening going through my vagina and sometimes into my inner thighs. But it wouldn't stay like that all day. Although, there were some days where he would do it so often that it felt like that. lol.
The extra skin that your husband has noticed may well be your inner labia, which is often covered by your outer labia when not pregnant, in pregnancy you have alot more blood down there and you can infact end up by looking abit swollen as well, this is due to increased blood flow.This also effects the inner walls as well. On the pain front, not too sure on that one, if you were further along I would suggest that it would be from baby rubbing its head on your pelvic floor muscles, this can cause a shock like sensation in your vagina, but if its hanging around most of the day maybe its just a pressure thing, try and do your pelvic floor excercises and see if it helps, or go and see your doctor