Cluster of tiny hard itchy bumps, maybe bites on my foot only?

My boyfriend and I both get clusters of what seem like small bites on our feet. They itch extremely bad when they first show up and take several months to go away. A new one or more will show up again in the same cluster after several months. They are only on our feet. I have three different places on my foot they keep showing up at, for almost 2 years. We both have them on the inside of our feet by arch, clusters of 3 or 4 at a time. They are tiny, kind of hard and sometimes have clear liquid but only if you really force it out. After some research, they don't seem like spider bites or warts. Any other kind of bug bite sound like this? We live in NYC so we don't go outdoors without shoes and socks, it seems to be happening in the house. Thanks!