Yep, it's likely bh contractions. My tummy gets that way too and I'm 25 wks. no worries, as long as u feel it baby moving that's all that matters..
Could be a few Braxton hicks contractions. Not harmful, ju as t your body practicing.
Baby may have been up against your belly. I am 34 weeks(tomorrow) and most of the time my belly is still soft. It just depends on how your baby is laying. :)