One of the shared challenges for people new to exercise and people who have been exercising for a long time is that when we try something different we feel it. It can be hard to tell if that discomfort we are feeling is just our bodies adapting to a novel experience or if we are doing something wrong.
The short version is that our muscles are a bunch of whiners who don’t like having their routines changed, even for their own good. When we first start swimming after a lifetime on land, different muscles have to work and our usual favorite muscles have to work differently. So they complain. They feel sore. They ache. This is normal. This is why we have ice and ibuprofen.
However, sometimes the muscles have a point. When we are just learning something, we may not understand how the form works. We may not be giving our muscles the best chance for a peaceful existence. If our pain persists for more than a day or two, we probably want to stop and reflect. We may want to do some reading or talk to an expert about what’s going on to see if we can refine the movements and avoid the suffering. Most of the time, when we manage to move with good mechanics, our soreness decreases.
Bottom line: a little soreness is okay; a lot requires some work to resolve.