Eye slightly puffy & painful?

any suggestions on what could be wrong with my eye? this has happened about three times over a course of six months. no impaired eye vision & has happened with & without contact lenses. the inner corner of my left eye gets a little red & puffy & very tender to touch. it feels like i was elbowed in the face when i touch it. which i know i wasnt. its also painful to blink & the pain goes about a half inch under my eye & down a bit of my cheek bone. its not severely debilitating & i can deal with it very easily. it usually goes away after several days to a bit over a week. thanks :)