I keep getting lumps behind my ears, they are small hard lumps i've had weeks at a time, now behind my other ear and i've had no infections, ideas?

Sebaceous cysts.: Most likely these are plugged oil glands in the lobe of the ear and in the skin behind the ears. This is a common condition. Warm compresses and observation is usually all that is needed and to leave them alone (no squeezing or picking at them). If they enlarge, they may have to be drained or they may drain spontaneously. They may require some antibiotics if infected. If in doubt, see your pcp.