I used to get the same thing , it sounds a little normal I get Braxton hicks ALOT & with the pressure . As long as you're not getting painful Braxton hicks where you feel like you can't walk or talk threw the contractions you're fine .
This is also my third pregnancy and I've had that pain after sex with all 3 of my babies. I over carried both and am 36 weeks now with this baby and still have that pain every time we have sex and walking around after definitely makes my contractions stronger. But they always end up stopping. But every body is different so all I can tell you is to just keep an eye on how you're feeling. If the contractions become strong and close together you should get checked out just in case. Best of wishes to you!