I have lump on my eyeball under my uper left eye lid. What cause this be?

A few things. If this was preceeded by a mild inflammation or pain in that area now gone, then it is most likely a cystic formation called a chalazion. This can be ignored or removed if a cosmetic problem. If it is inflammed, or growing or on the surface of the eyeball itself, then it needs evaluation by your ophthalmologist.