I get a similar thing, though for me it is actually BH's (They also have a penchant for pretending to be real labour for me as well lol) combined with a supected irritable uterus... I believe in the last 2 months I've only had 4 times, lasting half an hour to an hour, where my uterus hasn't been tight and uncomfortable. I also get a lot of pain because of it and just have to monitor it and keep a record of when it gets really painful and even more tighter than normal for my midwife.

It's good that bub is still kicking strongly - it might just be the way bub is sitting too, I know I get pain in certain spots that don't normally get pain from BH's when bub stretches out a certain way eg, across the top of my uterus lol