Hello, welcome to HCM,
The lump in your scalp may be a lipoma
or epidermal cyst
or a benign or malignant adnexal neoplasm
To diagnose it, you need a thorough clinical examination and do a Fine needle aspiration cytology from that particular swelling.
But, before doing a FNAC you need to do a X-Ray of skull to exclude any cranial extension.
So, consult with a general surgeon
for clinical examination and ordering the investigations required.