Hello. Thanks for asking from HCM. I can understand your concern. You have already read about scalp swellings. As you have found that, this swelling is tender on pressing, firm, mobile on bone and present on right lower part occipital bone, most probably it could be a cyst like swelling in scalp layer. Mostly these cysts are benign (non-dangerous). Most common swellings are sebaceous cyst, dermoid cyst, reactive lymph node. It can only be confirmed by biopsy or fine needle aspiration (FNAC). You can differentiate between these swellings to some extent. Like in case of sebaceous cyst, if it is carefully observed, a dark spot (punctum) can be seen over it. It is painless, but may be tender on pressing. Treatment is complete surgical excision of swelling with capsule. Mostly it is down under local anaesthesia if patient is co-operative. Dermoid cyst is similar to sebaceous cyst, but without punctum. If swelling is moved to one side, bony defect below it can be felt. Treatment is similar to dermoid cyst. Reactive lymph node is usually associated with some scalp disease like dandruff, skin infection, may be TB if you are from tropical country. Diagnosis can be confirmed by FNAC. Do not be scared. Thanks. Hope it will help you. Take care.