One of the things that happen with an anterior placenta is that for you to feel kicks through it (your placenta has no sensation. Neither you or your baby can feel anything that happens to it) your baby needs to give a fairly strong kick. At this stage your baby is not strong enough for you to feel any of her kicks through the placenta. You can only feel the kicks that hit your uterus directly. And therefore, depending upon the position of the placenta, it feels like your baby is only kicking in the one spot.
Your uterus can and often dose spasm during pregnancy. Braxton Hicks and labour are the uterus spamming.