What Causes Movable Lump On Side Of Neck And Cough?

My five year old has just developed a small soft movable lump on the side I her neck and she has a cough is this normal? Also my three year old son has a cyst like pimple that causes him pain at the base Of his hairline on his neck it comes to a head and then disappears and won t come back for a few months is this normal?