What is this lump under my scalp. you can move it a little and its been there as far back as i can remember but seems its got bigger. doesnt hurt?

Likely a cyst: A cyst is a pore, or hair follicle unit that has become filled with sebum, thick skin oil. These are common and can run in certain families. Sometimes they are squeezed and a bad smelling cheesy like material comes out. Some people have more than one, and they can be found anywhere on the body. They can be removed by a dermatologist.