my dog has a fluid filled lump in her ear flap. It's been there maybe 1 or 2 days.
Sounds to me like your dog may have an aural hematoma, and your description of it is pretty close to right on the money.
An aural hematoma is formed generally when a dog shakes her head so vigorously that it breaks blood vessels in the ear and these vessels cause the blood to leak into the space between the skin and cartilage of the ear.
Most vets will treat this by doing a surgery to remove the fluid and then tack down the skin to the cartilage so no more can build up.
It looks like you will need to see your vet to have this resolved. An aural hematoma is quite an uncomfortable thing for your dog.
You can read more about aural hematomas here: http://www.thepetcenter.com/sur/hema.html
I hope this helps!!