nasty red bumps on my scalp

Hi, I've had these bumps on my scalp for quite awhile now, only one is really big and red..another is large but flat and red and a few others are smaller raised and not as red. Can you tell me what these might be caused from and if you know of any way that might get rid of them? They don't really hurt unless i rub them. They are part of the skin and move with the scalp. The larger red ones look like they might be infected moles. Thanks for any information that may be provided. Tweet