Hello. Thanks for asking from HCM. I can understand your concern. This lump at the junction of neck and head could be : Normal bony protrusion. Normally our occiput is little protruded and round. You can think of it if it is bony hard, immobile, lump is continuous with rest skull bone and skin is freely mobile over it. It is a normal finding. No need to do anything. : Actual Swelling. It could be due to bony swelling or some cyst. Bony swellings like post traumatic, calcified hematoma, osteoma. Cyst like sebaceous cyst, dermoid cyst. These swellings will be felt separately from skull bone, sharp margins. Bony swellings feel hard, immobile. Cystic swellings are firm, mobile. You can correlate your findings and reach unto some conclusion. In case of actual swelling, consult doctor. Tissue sample or biopsy will diagnose the swelling. Further management will be decided after it. For headache and dizziness spell, you can give him painkiller like Diclofenac sodium after proper prescription. Ask him to take proper sleep. Get his vision checked up to rule out possibility of glasses. Thanks. Hope it will help you. If still in doubt, consult doctor. Take care.