I have a lump on my occipital bone. It is hard, non movable, painless, and is on the left side. What could It be? I suffer from constant all over pain

Occipital lumps. The most common cause for an occipital lump is trauma, from either direct bang or from a MVA. The two most common causes for systemic pains is Lyme Disease and Mold toxicity. Get checked.