Great (and popular) question.
As you are aware, a progressive lens is one in which the wearer has correction for distance, intermediate, and near vision. The lens is fit with the distance prescription near the pupillary center of the lens, or the area where the wearer will be looking in primary gaze. As the eye moves down from that point, a gradual addition of power is provided to allow for focusing on closer objects. This transition from distance to full near correction, as you likely know, doesn’t occur throughout the entire lens. Instead, there is a “channel” in the lens where the prescription resides. Accordingly, the eyes need to be within these channels for clear, comfortable vision to occur. Outside of the areas of prescription, a wearer will often experience the distortion or “swim” you mentioned.
One thing I hope you can take away from that description is how important the fitting of the lens is to each patient. If the lens is fit too high, low, left, or right, it will make it very hard for clear, comfortable vision to be provided as intended. So the first recommendation for you would be to return to your provider and describe the issues you are having. Often, a small adjustment in where the frame sits can make a large difference in how you see.
Assuming everything is where it is supposed to be, understand that there are different progressive lenses in the marketplace and each is different. Some will emphasize distance clarity, some will emphasize intermediate vision, and some will provide wide near zones. The selection of a progressive lens, therefore, needs to take into consideration a patient’s goals and objectives. For example, someone who drives for living has different visual needs that someone who knits/sews for a living and each would likely require different types of lenses to see their best. Your lens might not be a design that works best for what you need it to.
The final point to bring up is that a regular progressive lens isn’t necessarily the best option at a computer. Yes, many people wear them for the computer and do just fine. The reality, though, is that asking a wearer to look through a restricted area of a lens is a slight compromise…especially when there are other options available. Another idea to discuss with your provider 😉
