Has anyone ever had dust inside a lens?

I took some photos last week, using my D7000 with the stock Nikon 18-55 kit lens, and noticed some dust specks on the photos. I’ve just swapped over to my 35mm 1.8 and they are gone.

I’ve cleaned both ends of the lens but they are still there.

Scratch that. It’s the sensor that needs cleaning.

I have some lenses with bad dust and it doesnt normally show up in photos, just kills resale value. You can check if its sensor spots by shooting something like a white wall or ceiling wide open and they’ll appear.

Yeah, already done that. It’s the sensor. I guess I’ll need to get a sensor cleaning kit