my 10 months baby boy has 6 to 8 lumps around his back neck and head..are painless and of fixed size,what could be the reason for this? please answer

A. Lipoma if you may have heard of it is just a fat ball in the body so it could be the same thing that your child is having since it is of at a fixed place and fixed size is maybe they can be little bit movable but still since it is about your child I would advise you to consult your doctor for a personal evaluation