I have a ton of these things. I used to think they were inflamed and knotted muscles, but my massage therapist tells me otherwise. I have a hard time telling which lumps are lipomas and which ones are myofascial trigger points, especially since most of them are in my back, so I'm not sure if any of mine are painful.
Humidity. The most common cause of condensation on double-glazed windows is humidity. The outside window is colder than the inside window causing fog or frost to build up in-between the two panes. The window and house is extremely airtight and cannot breath.
Historically, windows were single glazed, with a single pane of glass, but today, there are a number of options for window glazing. Double or triple glazed windows create more insulation, making a structure more energy efficient by reducing heat loss through the windows.